Saculia

iTrader: (1)

My stock 305TPI developed a knock (or a couple of them) and is now in the shop for a complete rebuild from the oil pan up.
They are boring it out to the next size, installing new pistons, new bearings, new timing set, rebuilding the heads, reconditioning the connecting rods, and also resurfacing the crank shaft among other things. I took it to a specialized shop that supposedly does not cut corners on this stuff. My question is this:
Is there a preferred brand for the internal components that they are replacing, as opposed to a cheep brand that is not as durable?
Since most of the money I am going to be spending is on the labor, is there something that could be installed instead of the factory equipment that would give the engine a little more power. I have heard people putting in roller tip rockers and things like that. What would you guys do if you were doing this?
My intentions are to keep this as a numbers matching car, but don't want to go too wild with the internal mods.

Apeiron

Flat top pistons, a warmer cam, and maybe some head work, if it's in your budget. Don't let them deck the block if you're trying to keep it numbers matching.

Adrians91Z28

if you dont want to get into the motor tooo much..

then just do the pistons, cam, and a little work on the heads ..

i put vortec heads, edelbrock hi flow vortec intake, comp cam, flat top pistons, hooker 2055's and some other things .. along with a complete rebuild like your doing .. only i did it all myself (except the machine shop work)

i would at least consider the pistons (look to summit for a rebuild kit, around $320 and come with new aluminum flat top pistons), comp cam 08-501-8, hooker 2055 headers, and get the heads worked to handle the lift of that cam ..

now if you do that .. it will wake it up a good bit from stock .. and you wont notice anything except a really nice exhuast tone, and the headers (somewhat of a tight fit)

im running that cam and love it .. it has a TON of power at 3800 rpm .. yet has enough low end torque to throw it up in fifth gear at 35 mph (which = alot better gas mileage for city traffic) .. right now without a tune im getting 20mpg .. but you should get more with a relatively stock setup ..

oh .. also .. invest in a good cat back system and make sure you cat isnt clogged / get a hi flow one ..

i would think doing those few things should put a smile on your face during your drive to work , yet not seem like you built a race car ..

Apeiron

Avoid the pistons from a cheap "rebuilder" kit, they're usually missing about .020" of compression height for piston-to-head clearance safety when installed into zero-decked blocks by shade-tree engine assemblers who don't check such things.

Saculia

iTrader: (1)

Apeiron,
forgive my ignorance, but what is decking the block? Is this something that is done in order to increase the compression of the motor? Is it necessary in a rebuild like I am doing?
Also what brand of pistons do you recommend?
Thanks for your suggestions.

Saculia

iTrader: (1)

What advantage do you get with the flat top pistons? I don't even know what kind of pistons come stock in this car.
What kind of head work would you need to do? Do you need to get a different size valves?
I am sorry to ask all these questions, but I have never had to deal with this stuff before.

85gulstrandTA

How many miles on the car B4 the rods problems? Was you right foot heavy or do you push with both feet like me? My floor boards are convex under the pas pedal..ha..ha.
I may be doing the very same thing soon only my car is missing the motor. I'm in CA. so smog is a harsh factor. You need to spend the money on the motor based on what your plans for the car. To do the job right there are basic that may only apply to you. What are your plans with the car? what do you want it to do for you ?

Saculia

iTrader: (1)

The car had 123000 miles when the problem happened. I have owned it for about 1 year. The previous owner used to drag race the car, and I underwent quite a bit of work to get it to a point where it seemed to run well.
My foot had been a little heavy at times, but that was not frequent and I usually never exceeded 4600 rpm.
I had just spent a bunch of money on repairing an intake manifold leak. The car was leaking a little bit of coolant externally. I had the intake gaskets replaced. When they went in to do the work, two bolts at the back of the engine where the the intake manifold bolts to the engine head were broken and just left that way (possibly by the previous owner). So who knows what had gone into that engine.
The night my engine started knocking I was stuck in the snow, and was trying to get out by rocking the car back and forth. I never even hit 4000 rpm. After I got out of the snow, as I was driving down the road, I noticed a slight tick, that eventually turned into a knock (it took about 10 min).
So now I am rebuilding the engine. A local engine shop is charging me 3200 to do this.
I intend to keep the car as a matching number car. I am not interested in running 12s, but high 13s would be fine. I don't want to compromise fuel economy and reliability. I am not interested in making it the fastest car on the street. I want to make it a nice and fun classic muscle car. Most of what I am spending on this I am sure is labor. I am curious to know what are good parts to put in to gain a bit more power, while retaining the stock TPI, and without spending alot more than the $3200. It is an expensive repair for me.

85gulstrandTA

Ok Great, so numbers matching good power and mileage. Basically very near to what I'll be doing only I'm using the 305 for smog and mileage. the price seams high so I assume that include R & R also. The machine shop should be some one you trust and will explain thing to you, after all you are thier customer. the block will need to be taken all the way down for inspection and cleaning to start. Inspection tells you want you need, is the block good if not #'s matching is over and you have more choices(like a 350). Let's assume the block is good. prep the block to be rebuilt doing what it NEEDS based on what is seen...align honing the crank due to the crocked wear pattern on the bearing. helps true the crank to the cylinders. ...the bearing (crank and rods)tell a story by the wear patterns...what about the crank and rods are they ok to reuse if so, do so nothing wrong with using what you have at this power level you could grind the crank 30 on the rods and mains and be fine. They do this on dump trucks with tons of weight on them and they work non stop. If the crank needs replaced and you want to stroke the 305 to 331 now is your chance. let's assume it's good to. Let me back up a bit with all this assuming if you see any spots that got hot enough to discolor the block,crank or rods very deep, I would not use those parts. so the block and crank are ok to use. Next are the rods, the best path IMO if they are ok to reuse then recondition them and put new bolts in them. that will get us to the pistons because if we had any changes on the block or crank we would have to do something else. IMO the best money for pistons for under 400 hp is Keith Black's Claimer series pistons with flat tops, almost as much silica as their regular Silver Lines, and the prices are good. get about 9.5 CR. with the vortec heads. Afer all the parts are comfirned then you will need to balance the motor.This will be the base to having a 100,000 mile rock solid street car. Now you will need to cotact cam company with all your info to get the cam that will work in the rpm range you want. manual trannies help if you wanted a little larger cam. I using a 700R4 overdrive and will need to meet smog so .204-.212 @50 is the max I can go in my 85 TA. Comp Comp/Speed Pro will Know the best cam based on everything. the comp 08-501-8 cam called out earlier is .212/.218 @ 50 int/ex. just guesting with everthing I would use you would be over 300 hp and far more tq. As you cuurent motor was well used you may have had what 170 hp? I think your face will be hurt form smiling so much. with more power comes more heat so make sure the radiator is up to being part of the fun. A good time to look at the Clutch and flywheel too.
I feel this is the best bang for the buck and it will last, be good on gas and bad on tires. I already used this same set up on a non roller block 350 for my wife's car a 63 conv. nova. I looked at many dyno projection. It looks to be a 310 hp and 380 ft trq motor she will have more power that she ever has had and for 100,000 miles with a 700R4 and 3.42 gear in a 2800 lbs car I thinking 25 mpg is reasonable....my bed time......Cheers

Apeiron

Decking the block involves machining the deck surface (the surface where the heads sit) of the block down. It's done during a rebuild to straighten a block that's warped so that the deck is perfectly flat and perpendicular to the cylinder bores, or it can be done to increase compression by reducing the volume between the piston face and the deck surface. The problem is that the most important matching numbers on the engine are stamped into the deck surface just forward of the passenger side head, and decking will obscure or obliterate them.

I don't know that any one brand of pistons is any better than anything else for your application, as long as they're not the rebuilder types I mentioned.

gmgod

For the love of the almighty, man..... Why are you not putting this SAME amount of money in a 350?????? I've had several L98 and LB9 cars over the years, and if they're in good tune, they get nearly identical mileage. If you're worried about #'s matching (I not sure why you would be) then keep the old LB9 on a crate somewhere.

If the machine shop has'nt started on the 305 yet, do yourself a HUGE favor and bring them a 350 core to do instead. I'm not trying to be an @sshole here, just trying to help. If you blow that much money on a 305, you'll be kicking yourself in the @ss for years.

85gulstrandTA

gmgod I agree with you, in my case here in So. Ca. you neen to fear the smog police. There are ways to work in the shadows of the smog laws. My car came with the LB9 so I don't want to give them anyting to get thier teeth into me. Mine 85 had a 406 in it, I pulled the 406 to put in my 70 camaro and can get a 305 here in Ca. for next to nothing, a few hundred dollar with well under 100,000. If you have time to wait, some guy will give you one for free. For me the 305 is a cheap way to make the car street legal because I have none of the TIP, smog stuff, or anythig . Before the motor go's in I can check it over maybe hone, new rings and bearing a little better cam these cars are heavy so tq is needed to move them.Not worth it to me to stroke the 305. A 350 would give more power per dollar and putting the 305 on a pallet if you have room is a great idea. Then you can do whatever you want and not worry about the OEM #'S matching. The 350 would cost less on pistons and on 2 pc rear main seal blocks the cranks are the same "442" casting. Not sure on the 1 pc rear main. The 305's weak link is the bore size that shrouds the Intake valve. Maybe talk to the machine shop see if they will do the 350 for less money. Get a used roller cam block and rebuild it, to save more money. that way all the roller lifters, crank, rods are there, and use the same idea as above. If the 305 has damage like spun bearing that scorced the block then move on to the 350. I know a few guy that have tried to use a block with spun bearing over and over thinking they can make it work. Once the bearing spin and you get into another snow bank and stert putting some stain on it it only takes once and you are right back to where you are now. If you get a used engine to start with know the history or get a rebuilt short block fron the machine shop. Here places like speedomotive sell machined short block for just over a grand and you can tell them want you want. Local machine shops are a great resource and if your into cars get a relationship started. Say you have time on your hands. Ask them to look for a good rebuilable core coming in that some one else is say moving to a big block more wants a aftermarket block. Work with the machine shop. It's a large investment and you want to be happy with the out come so you can refer them customers too. That is what they get in return for doing a good job at a fair price. Be honest with them up front so all ends well. If I was not it the smog police hell I would use one of many of my 350's sitting in my garage. I wantted to but like rebuilding a motor with a spin bearing we all have to make choices. I'll play it safe the 85 TA, and get in the 70 camaro with the sbc 400 when I want to set off import car alarms at the mall when I go by them.
Cheers

Saculia

iTrader: (1)

I do agree that the potential of a 350 is far better than that of a 305, in fact for the same amount of money I could have gotten a 350 crate engine, however, I would like to keep this car mainly what it is, except for a few internal engine mods while I am at it. I am not sure that the 5 speed manual in the car and also the stock 10 bolt 3.42 posi will handle the extra torque of the 350.
This car has a sentimental value to me. It came as a 305, and I would like to keep it with the same engine. Sure it will not match the performance of a well built 350, but I think that a properly built 305 with the 5 speed manual and the 3.42 rear should be able to dip into the high 13s. That is all I want from the car.
This car ran in the mid 14s stock. It was rated at 230hp and 300 lb ft of torque from the factory at the motor. I am looking to get a few more ponies on top of that, nothing crazy.
The comp cam 08-501-8 is an option that I am considering, but don't know what needs to be done to the heads for the engine to be able to accommodate that cam. At this point I can't afford new heads, so I am going to have to make use of the heads I have. My car currently has the L98 camshaft in it. I am curious how much of a difference the comp cam will make. Would it make a difference if I just rebuilt the heads to factory specs?
I also like the idea of going with a good quality flat top pistons. I think that I will be happy even with a 20 to 30 hp gain over stock, if I did not sacrifice reliability and fuel economy.
Plus I am afraid that if I did something too wild, I may blow up the 5 speed trans or rear diff.

Adrians91Z28

i have the comp cam 08-501-8 .. i like it alot .. has a really nice tone to it / very slight lope .. and you can run it on the stock tune ..

ive been told in the past that the comp cam is slightly bigger than the l98 cam our 305's came with .. but it has much better ramp profiles ..

i think if you put in flat top pistons and that cam .. you should be looking at atleast 45 - 50 hp gains .. depends on the compression ratio ..

but i would atleast get a set of headers .. they make the best "bang for your buck" when it comes to performance upgrades ..

Apeiron

Probably not without head and exhaust work to go along with it.

85gulstrandTA

I'm not sure how to get you the link on the artical that Super Chevy did for a smog legal 305. 431hp and 470 ft tq all in by 5700 rpm. I just shows the 305 loyal GM fans that it would be respectiable in any car or truck. Kinda neet to tell the import car that cann"t get past seeing your tail lights that you don't have a 350 or 383..with good planning and spending the money in the right places with a 5spd you'll see 13's and get 25 mpg. as far as the rearend go's when your tire spin it's not as hard on the axels as when the car hooks hard. knowing the weekest link in the chain will let you make the right choices. IMO Lots of car lover are lead down a path to remove money from thier wallet when you may be buying a nice part you don't need. I would not use high dollar parts on a motor that makes 400 hp. Spend the money on machining the block and internals for long term use is better money spent. Listen and understand what the machine shop is doing if you do not understand how can you make a dession, be part of the proccess. It's be a lesson you can use over in life. Let us know what the machine shop says about your block. crank, and rods. Once that is inspected then the fun begins. I just found a 700R4 so I'm right behind you. I have a motor selected that I will check out in a few days. Like you it will be a 305.
Cheers

85gulstrandTA

I forgot to ask what the machine shop is charging to do the heads. Sometimes it makes good sence to buy new due to the price of reconditioning the heads. Your heads cam and intake all need to be on the same page together. One weak link in the chain can deplete the gains of the other. Worth looking into after all looking cost 0...

Saculia

iTrader: (1)

Thank you for the sound advice. They have not broken things down to me yet as to how much the machining of the block would cots, and how much the rebuilding of the heads would cost and how much the parts themselves would cost.
They told me that the whole thing will cost $3000 to $3200. I already placed a $1600 deposit, which was required for me to put down so that they can start the work.
They said that they needed to get a couple of jobs finished before they could get my car in.
So tomorrow I anticipate that they may be pulling the engine out. Once the engine is out and apart, they said that the mechanic will give me a call and go over things with me.
Your suggestions have been very helpful. They give me a starting point to begin thinking about this process.
It is a lot of money, and I did not anticipate to have to spend it on this now. I wanted to have the car repainted first, and drive the car with the engine the way it was, but the knock sort of changed that. So now I am rebuilding the motor.
I am sad that my engine broke down, but I am excited about the rebuild.
The shop said that they will recondition the connecting rods and turn the crank. The oil in the engine was very clean when the knock occurred and I don't suspect that too much damage was done to the block or the crank.
Prior to the engine breaking, the car seemed to run well, and did not consume any oil.

Saculia

iTrader: (1)

What headers can I get that work with the dual cat system for my car. I have seen some systems for the dual cats in the 4th gens, but not for the third gens. I sort of want to keep the dual cats. I am currently not running a muffler. The dual cats empty in a 3 inch pipe and it goes into a muffler eliminator with dual tailpipes you can't see under the bumper. The sound the car makes with the dual cats is very nice.
I will keep you guys posted on the rebuild and also on the results to follow.
Thanks again for your advices.
----------
What kind of head work do you think would be necessary for that cam and piston combination?
Thanks

Apeiron

The XR264HR he's suggesting is pretty mild and low-lift. You shouldn't run into any clearance problems, so you could use stock heads. You could have the spring pockets and valve guides machined to run a bigger cam, though. You might also have a little porting done.

Adrians91Z28

you cant run that cam on the stock heads .. the stock heads only support around .460 lift

that cam has a lift of .480 / .490 with 1.5 rockers ..

so you would have to get some work done to the heads so they can handle the lift of the cam ..

but i just went to summit and picked up some summit racing (trick flow) vortec heads that handle up to .520 lift and have a 1.94 intake valve .. only cost $280 each .. oh, and they come with a 3 angle valve job

it has a very slight, yet noticible, lope to the idle .. and it pulls really good at low rpms .. i can run mine and stick it up in fifth gear as low as 35 mph which is at 900 -1000 rpm .. but it really kicks butt when it gets up to 3800 rpm ..then the motor screams and kicks you in the seat .. i can feel my powerband start around 2000 ... but pulls really good in traffic at low rpms ..

if you are going to drive it daily ... i'd recomend it .. you'll be really happy with it .. i wouldnt go much bigger for a daily driver b/c of gas / idle issues ..

Saculia

iTrader: (1)

I don't intend to go any bigger. I need to see how much they would charge to do the machine work to my heads, compared to what it costs to order the heads you recommended from summit.
This site that sells the cam suggests that no other modifications are necessary to be done with the installation of this cam. Is it the right cam?
Please, take a look at the link. I don't know much about this stuff. http://www.lonestarracing.com/shop/p...oducts_id=4524

Adrians91Z28

yea .. that is the right cam .. same one im running

but im sure ive seen on multiple posts that the stock heads wont handle the lift .. i think that "no modifications necessary" means that it doesnt "need" stuff like an adjustable fuel regulator, custom prom, upgraded exhaust, etc ..

maybe someone else can chime in on if it will clear or not .. but if you get vortec heads .. you have to get a different intake manifold like the edelbrock or scoggin dickey vortec tpi hi flow base ...

if you have to get work done on the head .. i think you can do something with shims / offset collets (never used them but heard of them being used) instead ..

as i said ive never done any work .. or had any work done to heads .. so someone else will have to help with that info ..

Saculia

iTrader: (1)

Well,
the shop is going to be rebuilding the heads. I can't really afford a new intake for the car. I think that that's going to be a bit too much for what I want to do. I will talk to them and see if the stock heads can be modified to handle that cam, and also how much extra that modification will cost.

85gulstrandTA

You should call comp. cam or other cam companies tech line tell them what you want and they can give you the cam that a computer says is best. Heads are power, but so is a cam, and your intake needs to be in the same RPM range as the rest of the engine. Your c/r will also play a part in this. The more effiecent the heads are the more C/R you can run (also higher elevation allows higher C/R). IMO a broader tq curve is more impressive that peak hp. Your manual trans will allow for a larger cam if you want. The heads and cam might need to be dialed in at about the same time. After the motor is done what for red flashing lights, seams to be a side effect of long awaited tire smoke..ha..ha

Orr89RocZ

iTrader: (20)

tell them to setup the heads with screw in studs and machine down the guide bosses. should be about 100-150 for the stud work, 36 for studs, and another 50 or so for guide boss grinding.

For mild cams, you wont need much spring so stock pockets could be fine. they make a bunch of stout 1.25 inch diameter springs like stock that will work. Comp 981's are a good stock style spring.

your stock heads, with a cam like the 501 grind or 264hr as its also known should be capable of a high 13 second pass on good tires and hard launch. mildly cleaned up heads will be greater benefit but not necessarily needed. i think. porting the TPI intake could help. siamese it alittle. Then run either the 501 or 502 cam from comp. Or something similar. SHould make a strong 305... it will need a tune tho

Saculia

iTrader: (1)

OK,
I just got off the phone with comp cam, and they said that the stock heads on my car will be able to handle the extra lift of the xr264hr. I will need to upgrade the springs.

Saculia

iTrader: (1)

What does grinding the guide bosses do, and what is the benefit of the screw in studs?
Thanks

Adrians91Z28

if your gonna spend that much rebuilding the motor .. i would go ahead and put in the extra few bucks to do some mild upgrades .. that way you can look stock .. yet do this when people least expect it .. plus you will be thankfull you did when you drive it ..


EDIT: response to orr89rocz
----------

grinding the bosses will give you more clearance to run the higher lift cam .. i dont know if comp was right when they told you itll clear.. it would suck to put it all together and have a lobe wiped off or a pushrod bent b/c it didnt clear by .030"

and the screw in studs are a upgrade from the stock "push in" studs .. and wont have the chance of poping out when you get on it ..

Orr89RocZ

iTrader: (20)

screw in studs are there to prevent the stock press in studs from pulling out with high lift cams and higher spring rates. good insurance

grinding down the bosses enables you to run higher lift cams. stock heads will only handle .480 lift or so. the retainer will contact the factory guide boss at .480 lift or so. going higher will help pull the studs out not a good thing at alllll!

comp is wrong thats why i dont like to tell ppl to talk to cam manufacturers

Adrians91Z28

EXACTLY what he said ..

i dont think comp keeps all the specs of every head on hand to answer questions .. just tell you what comes up on the computer ..

download comp cams free desktop dyno ..plug in your motor and i bet you it tells you the same cam that they recomend on the phone .. and it doesnt tell you that it wont work on the stock heads .. only says if you need different springs, fuel pressure, exhuast, intake, etc ..

85gulstrandTA

I would show the machine shop the cam spec's you are looking at and let them guide you. If you picked your cam then prep the heads accordingly. Something may work on paper untill mass production rears its ugly not perfect head, just needs to be checked in the real world. Also a 305 has smaller bores than the 302,327.350.400's that is why it is best to keep the intake valves around 1.94. I'm lead to believe that any larger causes intake valve shrouding. The larger valve in a smaller bore start to have a negitive effect. when the inlet charge enters the cylinder and moves around the intake vavle it hits the wall of the cylinder and well...that movement gets in it's own way..for lack of a better term. a way to minimize this is too keep the valve size reasonable and to put as much lift in the valve that makes sence based on what you plan are. In your case a .500 lift is pretty good. So setting the heads up with the screw in studs are one way. If the bugget is really tight the machine shop could pin the studs. They drill through the heads where the pressed in studs are and sheer pin them. Z28 springs are around 110# on the seat. I don't think the factory even pinned heads with Z28 springs (not 100% sure). however as we get older we learn that if you keep your foot in it untill pistons are swapping cylinders....some insurance is required. The top end you prepare for your 305 will also work on the other sbc's, the only mod would be if you later wanted to use top end on a 400 then all you need to do is drill the steam holes in them and your ready for them too.

Apeiron

It might be possible to get .495 out of it, and almost certainly if offset retainers are used. You can usually count on getting at least .480 from a stock head with adequate clearance, but it depends on the production tolerance of the heads, and the valve seals and retainers. Some people have reported getting .510 lift out of stock heads, some people have said they ran out of clearance at around .450.

Either way, there wouldn't be any question of it not fitting if the heads are machined. It's not a complicated or expensive operation, especially when the heads are already off the engine.

Comp reccommends their 986 dual spring for that cam, which would need the spring pockets enlarged. You could use a single spring with similar specs that would fit in the stock spring pockets, but if the valve guides are getting machined, you might as well have the spring pockets done at the same time. Regardless, I'd use screw-in studs, or at least have them pinned.

It's only money, right?

Saculia

iTrader: (1)

Thank you for your helpful suggestions. I will call the shop tomorrow and check to see where they are with the disassembly of the car. Hopefully they have pulled the motor out.
If they have gone that far, I will request to talk to the mechanic doing the work and find out a time when I can discuss all of these things with him.
I will keep you guys posted on the progress of this rebuild.
Your help and suggestions are most appreciated.
Thanks

85gulstrandTA

If you get a chance ask them to see the motor. If for no other reason so you can said you did. They could show you what they look for and what your looks like.

Saculia

iTrader: (1)

I do plan on seeing the motor. I spoke to the people at the shop today and they said that they do a lot of custom work like that. On Monday I will speak to the owner and go over the prices of how much extra it would cost to get the cam upgrade.
I intend on taking one of my old pistons home with me as a souvenir.
They have not gotten the car into the shop yet. They said that it will be about mid day on Monday that they will be able to get going on pulling the motor out.
I will keep you posted on how thing go.
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Does my car come stock with flat top pistons?
Would flat top pistons lower or raise my compression ration, or would it remain the same?
Thanks

Adrians91Z28

our motors come stock with a piston that is sorta flat .. but a true flat top piston will raise your compression ratio .. and so will a dome piston (shaped like a dome) .. and a dish pistons (kinda looks like a bowl) will lower you compression when u want to run forced induction (got them in my 89 mr2)

a cam upgrade shouldnt cost any extra labor ..its the same as putting the stock cam back in .. so if they charge you more b/c you have a new cam, tell them to shove the old one up there a** .. haha .. (that is unless its a different type of cam .. ex: hyd roller, hyd flat tappet, solid flat tappet, etc)

Orr89RocZ

iTrader: (20)

i know 90-92 fbody L98's had flat top pistons. I dont know what the 305's got. The older L98's like my 89 have 12cc dished pistons.

Adrians91Z28

my 91 305 had flat top pistons .. but the aftermarket ones were alot flatter .. the edges on top werent rounded off .. thats why i say there sorta flat .. the machine shop guy said that my new ones would raise the compression over the stock ones ..

Apeiron

Not all flat-top pistons are created equal, though... if you get a typical flat-top "rebuilder" piston, the crown will be shorter than a factory flat-top, and you can end up with less compression.

Orr89RocZ

iTrader: (20)

gotta check the compression heights and the valve relief sizes. generally flat tops tend to range in size from 4 to 7cc's. Some have 2 or 4 valve reliefs. That all changes the compression alot more than you'd think

Saculia

iTrader: (1)

OK,
So here is a link to the pistons I am considering:
http://store.summitracing.com/egnsea...8&autoview=sku

What do you think?

How much do you think my compression will be raised with these pistons?
How high can I go in CR before running into problems with detonation?
I still want to be able to use this car as a daily driver, so it has to be able to run on pump gas and be reliable. I have never ran it, and don't plan to run it on anything less than 91 octane. However, I don't have the know how to make adjustments to spark timing and things like that.

Adrians91Z28

mine had 4 valve reliefs and were 5cc pistons ..


EDIT: those pistons are the same as what i put in .. there very nice pistons (wish i could have one for decoration) but i coulda swore mine were 5cc instead of 6cc

Apeiron

You're wasting your money on forged pistons and premium gas.

Saculia

iTrader: (1)

Apeiron,
What do you recommend? I don't want my compression ratio to be below stock the stock 9.3:1.

Apeiron

Hypereutectic pistons and regular gas.

Orr89RocZ

iTrader: (20)

yeah you dont need forged pistons unless your revving very high making good power or plan to spray a 150 or more nitrous shot

85gulstrandTA

I agree waste of money don't get sucked into the hype of buying parts you don't need. I have domed forged in my race car(630 hp all nat. 4 blt main) and flat top 4 valve reliefs hypereutectic in my wifes car(310 hp 2 blt main) and my street car D shaped 18cc dished hypereutectic (450 hp 2 blt main) The brands I used is JE, KB claimer, KB silverline in that order. Speed Pro are also great pistons, I had a set for my wifes car but changed the bore size and odered the KB claimers. Hope that helps.

Saculia

iTrader: (1)

Since my car has only 2 valves per cylinder, why do I need 4 valve relieves on the piston?
I found some what seem to be nice KB hypereutectic pistons for about $189/set. These have 2 valve relieves and with 55cc combustion chambers, which I think is what my stock heads are, the compression ratio is listed at 10.4:1. Is that compression ratio too high to run on pump gas?
Would I need to change the ignition timing if I run the xr264hr in combination with these pistons.
Here is a link to the pistons:
http://kb-silvolite.com/performance....details&P_id=2
I also found these that have 4 valve relieves:
http://kb-silvolite.com/performance....tails&P_id=246
I unfortunately did not find any claimer series pistons for the 305. Everything I found was for the 350.
Thanks alot for all your help and suggestions. I am still waiting to hear back from the machine shop. If I don't hear from them by the end of tomorrow, I may just drive down there on Friday and talk to the owner in person.

Adrians91Z28

the pistons with 4 valve reliefs are just b/c its a "mass produced" piston .. and there is an arrow that is supposed to be pointed torwards the front of the motor ..

you can get the ones with two valve reliefs but i'd imagine there more expensive b/c it would be two different sets of 4, but you'd have to make sure the machine shop puts the rods on right (the little notches for the bearings are supposed to be pointed a certain way)