85c1500

Hi guys. New guy here. I joined this site because every time I googled 305 performance stuff this site always had the best info. Let me start by saying this is not my first engine build. I built my first engine 23yrs ago and have built several since. This is however my first 305. I know what some of you will say, get a 350. Especially when I tell you this is for a 85 GMC Shortbed truck. But I`ve got a 305 in the truck now and found a 305 roller short block cheap to rebuild and Im not trying to set any land speed records with this either. And I rarely use the truck as a truck. Its my daily driver and gutless as hell.

Ok so Here is what Im thinking,

305 oem roller block +.030
Speed Pro 5cc flat tops H534CP
L31 5.7 vortec heads with guides cut down for clearance, minor port work, upgraded springs to match cam and possible screw in studs/guideplates
Comp XR258HR-258/264 206/212@.050 .480/.487 112LSA
vortec performer with SMI Qjet.
1 5/8 headers and 2.25" flowmaster exhaust

Already have a 700R4 upgraded with 87-up internals. Planning to add a 2500-2800 stall and 3.73 gears.

Any thoughts? Before you guys say to go with a 350 that is a possibility but I`d like some input on what I have listed above.

aliceempire

iTrader: (14)

I may be looking at this wrong but those heads (64ish cc) and those pistons (+5cc) will have terrible compression on a 305. Depending on gasket and deck height it could go from bad to terrible.......unless I'm missing something.

85c1500

I figured about 9.3:1 static and 7.8-8.0 dcr. using a .035-.040 quench and a chevy small bore gasket. I have the exact specs at home.

aliceempire

iTrader: (14)

Something seems off. Flat top piston 305s had smaller chambers than the vortecs and they were close to 9.3:1. Again maybe I'm missing something.

85c1500

Were they true flat tops or did they have a small dish? What cc's were the pistons? The ones I found are flat tops with a 5cc top. I used the same compression calculator I have for years and it's pretty accurate.

aliceempire

iTrader: (14)

I did some guessing on common numbers like gasket and deck height, I came up with 8.7ish. Without your exact numbers I'm only guessing. Not as far off as I thought it would be but still a bit low.

Night rider327

iTrader: (13)

Your math is right on compression. I come up with around 9.27:1. I think that combo looks good. It will be a stout 305 with great low and mid range power.

If you plan to add 3.73 gears and 2800 stall, I think I would bump the cam duration up a tad though.. Maybe something closer to a 212/218 @.050"

85c1500

I don't have the exact deck height, gasket bore and compressed thickness in front of me but I got 9.3:1 and like I said, my calculator is pretty accurate.

Night rider327

iTrader: (13)

3.766 bore
3.48" stroke
4.100 x .015 gaskets
.025" down in cylinder
5cc dish
64cc heads

That's the numbers I used and got 9.27

85c1500

I actually use 3.796 for .030. Maybe I have the standard bore size wrong. I also used 4.0 for the gasket bore and .028 for the thickness. Can't remeber the GM number. I also use .010 for my deck height putting my quench at .038.

aliceempire

iTrader: (14)

Makes sense. I couldn't find a 0.2x gasket in a small bore. Also assumed .025 in the hole. As long as you have your ACTUAL measurements accurate then I think it'll be a good build.

Fast355

iTrader: (2)

I would run a set of 059s on that engine. Also 305s really enjoy single pattern cams. I am running a flat tappet Lunati 268 high efficiency cam in an otherwise stock 305 Vortec in a 1999 Tahoe. Plenty of power for that truck and has a very nice sounding idle.

85c1500

I did a Google search and found some ffom Chevrolet. The block will get cut to whatever I need it cut to. My machinist is pretty good about setting the quench up right. I can even shave the heads a little but I'm also considering the World Products 58cc torker heads. I didnt want to go to crazy on the camshaft since it will be in a heavy truck.

85c1500

Not familiar with those heads. I'll have to Google them.

85c1500

Looked up the 059 heads. They are the 305 vortec heads and not very popular. They don't flow near as well as the L31 heads and are not as easy to find.

As for the camshaft, the heads will determine what camshaft split you need. Vortec heads actually have a weak exhaust compared to the intake so they need a wide split. 12-14 degrees would be ideal but I would need a custom grind for that. Not worth it on this build. The AFR heads have a very strong exhaust and can run a single pattern camshaft.

Fast355

iTrader: (2)

Stock out of the box canadian 059s as they came on 305s from 1996-2013 outlfow any of the mexico 062 heads. They are plenty common as many trucks/vans and boats had 305 vortecs.

You are WRONG on the split for a 305, I have experimented enough to know. The small cubic inch engine needs to hold the exhaust valve closed a bit longer to make good low speed torque. I like single pattern 108-110° LSA cams installed 4° advanced in a 305. I can tell you right now you don't need 12-14° of split unless you are going to turn 6,000 rpm or more the entire time.

85c1500

Vortec 305's aren't common in my area but everything I've read about the vortec 305 heads is they don't flow as good as the 350 heads.

I'm not wrong about the camshafts. Specific engines don't like specific cams. If you change heads then the cam needs will change. If you found that the single pattern cam works for your application that's great but to say the 305 lie a single pattern cam as a blanket statement is wrong. Go ask and cam grinder, Chris Straub or Mike Jones are who I think of for a custom grind. First thing they will ask is what heads. Doesn't matter about the engine size. What determine camshaft needs are the entire combo.

Fast355

iTrader: (2)

Definately not a blanket statement. The 305 doesn't have enough cubic inch to need the extra duration and lift until it gets to a very high RPM. You are building an engine for a 4,000+ lbs truck, not a race car. I was turning 110 mph in the 1/4 with my 305 in a 2,800 lbs car. Same engine was in 3 different applications (including a fullsize G-van) and 2 different sets of heads, same cam. I tried both a single and dual pattern cam in the build to start with. In the heavy van the dual pattern cam was very soggy in overdrive on the highway. The single pattern cam of similar intake duration made much more torque.

You can read the 305 head info all you want, I have had both sets on a flow bench. A set of take-off mercruiser 059s from a freeze cracked L30 305 absolutely blew the cracked 062s off my circa 2005 L31 hecho en mexico crate motor out of the water on the intake port despite the 1.84" valve. The hecho en mexico heads peaked at 214 cfm @ .450" where the 059s flowed 224 cfm @ .500".

Stan Weiss has 059 numbers on their site to backup what I am saying. Car Craft has flow numbers in one of their budget 350 builds to back my low flowing 062s too.

Also keep in mind with the 305 you have to deal with intake valve shrouding. Your intake duration is going to need to be increased to get the airflow through the intake valve at higher rpms. The 350 heads also have poor combustion properties on a 305s small bore.

85c1500

I can see we aren't going to agree on this. I'm just going to say this and then I won't address it again because as I said I've been building engines for almost 25 years and none of them were stock. I just haven't built one this small.

The size of the engine by its self DOES NOT determine what duration the engines needs. It depends on the size, intended rpm range, what heads are used ect. A head with a weak exhaust port, which is pretty much any OEM head, will usually make the most power with a split pattern camshaft. With a head that the exhaust port flows at least 70% of what the intake flow then you can run a single pattern or a very tight split. You CANNOT pick the camshaft until you know what head you are running regardless of what the engine size it. Head over to team chevelle's performance forum, speed talk or yellow bullet and run your theory past the pros. They will tell you the same. I am building a truck engine but that doesn't mean I can't set it up the best I can. No way would I run a single pattern camshaft with vortec heads without some heavy exhaust porting. I am not going to spend a more time arguing about this. You can disagree if you like but if you just want to get into a pissing match over it I won't do it so you can just move along. Merry Christmas

Fast355

iTrader: (2)

Well good luck with your build, I am DONE sharing my 305 build experience with you. Keep in mind I was pushing a 5,300 lbs (+ 240 lbs driver) 1983 G20 van to a 15.002 @ 93 in the 1/4 with a stock stalled 4L60E and 3.08s. I have nothing more to offer. I had 1.94/1.60s in my 059s and had them flowing great for my build. My split pattern cam was on 6° bigger on the exhaust. But since you seem to know it all, I won't go any further.

The Tahoe I mention on a flat section of road, over a 1/4 mile data recorded run, trapped 86 mph with a driver and passenger. Right at 5,500 lbs and 86 mph, puts it at a calculated 280 HP. The truck has a L30 305 that is stock except for the 268 cam and the 350s dual cat exhaust and a retuned PCM. Getting 22 mpg at 70 mph turning 2,000 rpm in that too.

85c1500

So are you saying you had the best performance with a split pattern cam because that is opposite of what you were saying before.

I don't know it all but I do know that it takes more than a certain engine to know what type of cam the engine needs. Cylinder heads play a huge part in selection. Plain and simple. I'm glad your build worked for you but I'm going to stick with what I know. Like I said I've never built this small of a engine so I wanted to get some input on the parts I plan to use.

Fast355

iTrader: (2)

Also the big van went 14.63 @ 96.55 with a Yank 2800 and 3.42 with a locker in the rear and 295/50R15s in the back.

Fast355

iTrader: (2)

I had better HP with the split cam, but I saw higher average torque, especially in the low-midrange with the single pattern grind. Lets face it we are not at WOT all day, everyday on the street. The single pattern, tighter LSA cam brings the torque curve on much more quickly, especially under part-throttle.

85c1500

I agree with the tighter LSA but I will stand by statement regarding duration needs.

Fast355

iTrader: (2)

I also have a 97 Express with a 5.7 that I am running worked 906s with 2.02/1.60 valves in. They also have beehives, comp retainers, and were machined for guideplates and screw in studs. Running the L31 marine intake that has been ported. Also running doug thorley tri-ys. My cam choice was the little GM factory billet steel 196/206 @ .050 marine cam and 1.7 full roller rockers. Really wish it had something around 212/212 @ .050, but I just could not justify another faulty Comp cam cast core roller. I have a 4L80E behind it and ran the stock converter with 3.73s in the rear. For 3-tons it ran very well. I am currently dialing it in for a 2,600 rpm 10.5" converter.

85c1500

The ramjet cam works very good and I considered that cam as well but thought the comp would be a little better. You can get them in a bullet core. Just change the -8 to a -10 on the part number.

You mean 1.6 rockers right because 1.7 is not a typical sbc ratio.

Fast355

iTrader: (2)

Nope, I mean 1.7s. The LT1 guys commonly use 1.7s too. I had Crane gold self-aligning 1.6s on the engine for the longest. I put guide plates on these heads to run non self aligning 1.7s. Had to use custom length pushrods and drill out the pushrod holes in the heads. Also switched to perimeter bolt short valve covers on adapters to clear the top of the wider rockers. I had to stay with a short valve cover to maintain compressor bracket to valve cover clearance.

Also that -10 is something close to $500. The GM Marine cam is $160.00.

Fast355

iTrader: (2)

Also the Marine cam is DONE at 5,000 rpm even with the head work, big valves, and 1.7s. The Marine 305s were rated 250 HP and had the same cam.

85c1500

I usually only see that ratio with shaft mounted rockers. The gains over the 1.6 are small. would only notice it on a dyno. And if you did notice the difference then your camshaft is wrong for the application.

You didnt say anything about cost. You said cast core comp cams. I just took that to mean you didnt know they were available in a steel core. you also have to look at the grinds. The GM is more of a oem type grind, except for the 109LSA, with mild lobe ramps. The Comp with the same specs would make more power. Im not a Comp fan by any means but they happen to have the camshaft with the specs I want without going to a custom grind. Otherwise I would have Chris Straub design me a camshaft and I`ll betcha it would be a single pattern cam with untouched vortecs.


Im not really sure what your trying to accomplish here. I disagree with your thinking on how to select a camshaft and regardless of how many time you tell me it works for you, I know I wont do it. You already admitted that the split pattern cam made more HP. But then you said the single made more "average" torque. Id like to know what the actual torque numbers were for the entire dyno run for both cams. I`m already doing what I said I wouldnt do so Im going to stop because I dont care what you run. I would never pick a camshaft based on engine size alone and neither would any cam designer or engine builder I`ve had the pleasure of talking to. If you want to keep this going, just move on to the next thread bud because I`ve heard about all I need to from you.

85c1500

Im curious how long you have been running those 1.7 rockers.

rusty vango

a 0.030 over 305 has a bore of 3.766. stock , its 3.736

85c1500

Ok thanks. With that bore size adjustment I get 9.29:1. Still better than stock.

I used 4.0" for the gasket bore, .028 compressed thickness and a .010 deck.

Just taking the heads from 64 to 62cc`s puts it at 9.51:1 with a DCR of 8.04:1 Pretty close for a iron head engine and would probably need 91 octane but Im hoping the fast burn chamber helps. I was wanting to run this on 87. I may have to rethink my camshaft choice.

Fast355

iTrader: (2)

Not sure what your stock engine is, but my 1983 LE9 305 from GM had 53cc 14022601 heads.. From the factory it had flat top pistons with 6cc eyebrows that sat 0.025" down the hole.. It also had a wafer thin 0.018" thick 3.8" bore head gasket. Had a knock sensor, the 5 pin HEI module and a ESC module under the drivers seat. My parents had it from the timr it had 1,500 miles on it and it had never been into until I tore into it.

85c1500

The 305 I found is a oem roller block like I mentioned so it would not have the 601 heads on it. And since its a centerbolt head it probably has a dish piston. I actually have not picked it up yet so I have no numbers.

I`d still like to know how long you have been running those 1.7 rocker though. Im curious about something.

Fast355

iTrader: (2)

Getting close to 8,000 miles. In the next three days it is getting 2,200 miles put on it.

Remember on the small block chevy 1.7s it only moves the pushrod a 10th of an inch or so toward the pivot point at the stud. Check your pushrod length, rocker arm alignment, and pushrod to head clearance.

85c1500

The reason I asked is looking through some of your older posts I saw no mention of 1.7 rockers, only 1.6. I have no interest in running 1.7 rockers. If you have to move up the rocker ratio you already have the wrong camshaft.

Fast355

iTrader: (2)

Not necessarily true. The small block chevy is about the only engine that used 1.5 rockers. Fords and Mopars had 1.6s. Many big blocks had 1.7s. 1.7s are upgrades for Fords and Mopars. 1.8s are common on the LS. The higher the ratio of rocker you run the more aggressively it moves the valve. You can have more aggressive valve action without having the aggressive lobe.

I put the 1.7s on when the Etecs came off, worked 906s went on and the failing Comp 215/220 came out and the Marine cam went in.

I left Texas at 9:30 am with my brother. I am in Troy, Ohio north of Toledo. According to GPS I averaged close to 70 mph on the road running with traffic at speeds frequently 80+ mph. 1029 miles and thus far have used 58.4 gallons. I came into Ohio from Nashville up through the hills of Kentucky. I can count on one hand how many times the 4L80E had to kickdown on the hills an many of them were fairly steep and long.

85c1500

Any camshaft designer would disagree with you and so do I. You don't know as much about camshafts as you think you do. You are wasting your time posting here because you have no information of any use to me.

86LG4Bird

iTrader: (1)

Aw... you're not subscribing to Fast's Fantasy Fysics on Internet Engine Godliness?.......

Fast355

iTrader: (2)

Keep blasting at me if you want. It is your build and you will be responsible for your own failure if it doesn't meet your needs. Telling you from first hand knowlege, you will not like a 305 with too much exhaust duration in the RPM ranges it will spend 95% of its time at part-throttle in. Almost every cam company in existance will keep you happy by grinding those big split lobes on a wider than necessary LSA. Ever looked at a cam event calculator? When you add exhaust duration and widen the LSA to keep your idle tame and good vacuum you also open your exhaust valve sooner and sooner. The quicker you open that valve the more low-end torque you lose.

I made the same cam mistake with the first grind I had in my 2006 Dodge Ram 5.7. I had a 264/278 grind on a 114° LSA that was sitting straight up. Great top-end pull, NO torque. I pulled that cam out and put a 264/264° on a 114° lsa advanced 4°. Hemi heads out of the box have even worse flow split than Vortecs. In that big heavy Ram the small cam was noticeably quicker. Even part throttle in the 2,500-4,500 rpm range the truck responded well

85c1500

What gave you that idea?


Your right, its my build. So why would I listen to someone who has no idea about camshaft design? And then you compare a hemi to a 305? Come on dude. give it up. Im not buying what your selling and sounds like Im not the first person to do that.

Im new here but not new to performance. You dont pick a camshaft based on engine size. Go call ANY cam company and ask for a camshaft selection. doesnt matter what you need it for, just leave out the cylinder head info. Ill bet you anything they will need that cylinder head info. You want to know why those single pattern cams worked better for you? Because you had the wrong camshaft to start with. Just like when you installed your "1.7" rockers, which in every other thread I read of your you mention 1.6 so I know the 1.7 is BS. You band-aided the wrong camshaft with a rocker change. And what does that do? It makes the camshaft "think" its bigger than it really is so it acts differently. adds more lift, slightly changes .050 duration. If you had to do that you had the wrong cam. With your hemi you had to go to a single pattern camshaft because you didnt know what cam to go with it. If its got a worse exhaust than the vortec then it needs more exhaust duration.

Ive already said it once and guess I wasnt clear. I dont need or want your kind of help. And BTW, all this was for nothing because Im not doing the 305 now.

Fast355

iTrader: (2)

Its not the "wrong" camshaft, I just wanted more lift to work with the heads better, without losing a ton of torque that the small cam offers. That Hemi ran great. As far as it goes an engine is an engine when it comes to setup. Get a well balanced setup and it will run.


I went with a single pattern cam with the Hemi because I wanted to gain torque. The Dodge PCM does not like alot of overlap. Less exhaust duration and a wider LSA made the PCM happier and made it run alot better.

I am running 1.7:1 rockers. I ran 1.6s for years on several different engines. On the Express I was also running Etec170s. I recently made the switch after overheating the Etecs to the point of slightly warping them, causing coolant loss through the head gaskets. The Etecs need to be surfaced. I also had a 215/220 @ .050 comp cam that was failing across the flanks. I switched the heads, cam, lifters, rockers and intake manifold. I recently pulled the stock intake back off and put the marine intake back on and switched to coil per cylinder ignition.

I also never said use a certain cam based on engine size, I said use a specific cam based off the setup you were planning to run.

I am going to a 496 Mag HO cammed 425 HP 8.1 soon, but to each their own I guess. I will be putting Raylar roller rockers on that setup too.

Fast355

iTrader: (2)

This is what my Comp Cam sound like after the lobes started to go and started taking out the lifters. I went with a factory billet roller cam for cost considerations and reliablity. A 395' cam is $170.00.


Keep bashing because you don't know all the details. My setup works for me. In fact for a 350, I would be hard pressed to come up with a better setup. The only thing it needs is about 1/2 point lower static compression ratio or aluminum heads but other than that it is great.

85c1500

There you go bud. Said it yourself. Now that you realize your not the smartest guy in the room you are trying to backtrack. I dont give a sh*t what you did or what works for you. You dont know what you are talking about and thats the bottom line. And a "engine is a engine" is one of the dumbest things Ive heard. Takes more than a balance job to make a engine run good. Takes a planned out combo which you clearly havent grasped yet since you keep throwing camshafts at your engines. If you really want to make your engines run right contact this guy.

Chris Straub,

http://www.straubtechnologies.com/contact-us/

Beyond that just stop dude. I dont care to hear what you have to say. Ive known a few guys like you on other forums and your all the same. You try to latch onto some newbie thinking you can spread your knowledge and gain a fan. and when that newbie realizes you are full of sh*t you just keep trying to win them over. Give it up dude. Aint going to happen. Stop embarassing yourself and move on. This is the last time I even acknowledge you.

Fast355

iTrader: (2)

I still will not back down from the simple fact a 305 built for the street, running under 6,000 rpm with a 1.5" or 1.6" exhaust valve does not need a dual pattern cam to run well. Don't believe me, pickup engine analyzer and build a correctly spec'd 305 and start playing with cam specs. I have and it was very awakening.

The combo I planned RUNS GREAT. What are you missing about that? Go spend your money on the highest dollar cam you can, I will put my money in the intake, heads, headers, exhaust, driveline, use an off the shelf cam and beat you down the track or stoplight to stoplight. It really does not matter if I run 1.5 rockers or 1.7 rockers to get the valve action where it needs to be as long as it is there.

85c1500

You are full of sh*t and I will not back down from that. Playing with a engine analyzer is not real world results. and you have to know what you are doing which we all see that you do not. I have said it already, I dont care how good you think your junk runs. I dont WANT your input. Why cant you get that? Nothing you have to say interests me the least bit. Im done with you. If you reply again Im just going to block you and report you for harassment. Ive asked you to stop posting several times yet here you are again. Let it go man. How can you not be embarrased by your actions?

Fast355

iTrader: (2)

Defending my point and character is hardly harrassment to you. If anything you are the one that asked for advice and when I responded with solid information of what I have done, stormed in here and have decided to try to discredit the real world 305 and small block stuff I have actually worked on. I have a Tahoe running in the driveway this very moment with a cammed L30 and have had numerous other 305 setups over the years that have all made good power and ran well. I have nothing to be embarrassed over. An engine setup is merely physics and an engine is an engine in that respect. You are the one that wants to argue with no solid real world experience with this engine, not I. You have also continually tried to pin older posts against me with my setups to discredit me, that you have no clue about. I am a tinkerer by nature and what is in a specific setup may change 2-3 times a year as I experiment with new ideas and setups. Don't worry though, I plan to avoid any and all future posts from you.

85c1500

It is harrassment when I have told you several times to stop posting on my thread and I didnt want your help. You kept shoving it down my through even after I asked you to stop so you are the one who wanted to prove your point. You just dont get it. You cant prove a point to someone who sees you dont know what your talking about. You think your the be all end all of knowledge on a 305 engine? you dont know jack **** bud. And just because Ive never built a 305 doesnt mean I dont know what Im doing. I dont care about what you got running in the driveway. I dont care what you think you built in the past. You are a joke, everyone sees it. You wont have to worry about any future posts from me because Im blocking your dumb ***. Not to mention I only joined the forum because I was building a 305 and since Im not doing that now there is no need for me to be here anymore.

Fast355

iTrader: (2)

For anyone else actually building a 305 out there, this is why it does not need a dual pattern cam and responds best to a single pattern cam. The intake valve is so heavily shrouded by the small bore, especially a 350 1.94 valve head, that the intake valve needs more lift/duration to move the airflow into the engine. Split pattern cams are not really necessary or needed.



Even the engine masters 305 that made 394 HP @ 6,300 with Fastburn heads only ran a 9° split and oh also ran 1.65 rockers. Under 6,000 rpm the duration split would have done very little to help power and would have hurt torque down in the 1,500-3,600rpm range.

85c1500

for those of you including this ding bat that keeps posting on here even when I ask him not to that what to lear why this ding bat is completely wrong about his camshaft thoughts here is some excellent information from a guy who actually designs camshafts for a living. Google his name or screen name and you will find all of the information you need to know about camshafts. Fast355 is the last guy Id take camshaft info from.

http://www.chevelles.com/forums/showthread.php?t=374438

BTW, offset head dowels would do wonders for your intake shrouding issue. But Ill bet you knew that, right?