TxTtopZ

All the kits I see are -10cc. For vortec heads and all other variants, GM specifically says to use flat top pistons. Has anyone found flat top forged pistons for use in a 3.76" bore at a 383 pin height? Hypereutectics with high silicon would work too.

Orr89RocZ

iTrader: (20)

Doesnt je have them? Cp or diamond may make them too

TxTtopZ

All I have seen is forged 3.48" stroke normal pin height pistons. I have been here before (looking for kits ) and after finding numerous kits of better quality than Powerhouse and all they all say is that I can get some made custom. This is where I have always stopped. I'd like some Mahles with graffal coating, -5cc.

InfernalVortex

iTrader: (4)

Probably because the compression with -10cc pistons is closer to what you need with 305 heads.

Just a build a 350. Will probably be cheaper.

Orr89RocZ

iTrader: (20)

http://www.cnc-motorsports.com/cp-s2...-766-bore.html

Cp flat tops. Use with zero deck block and a 5.85 rod. Leaves em .025 in hole

Or 3.875 crank, 5.85 rod, standard deck. Leaves em .012 out block run a .05-.06 mls gasket

TxTtopZ

Checked SRP, JE, ICON, CNC, KB, Ross, Etc. Not luck yet. I agree that the 350 would be easier, but cheaper... depends. Thinking out loud here but the idea of a "hot" 305 has always sounded like a fun project. I can custom order pistons for a grand but that doesn't seem like a smart move given the HP result in this case. I would like to simply find a piston or even a kit that's near $1500.00 at the most.

Orr -
Using a 5.85" rod would work. But I don't see the CH working on those pistons... Correct me if I am wrong. I absolutely want to stay away from a shorter rod.... and use a at least a 5.7" piece. This I feel would be a better rod to stroke ratio and keep the engine happier at higher RPM's and when its a 305, that doesn't hurt.

I may just have to scrap the Fast Burn idea all together and go with the Trick Flows. It actually saves me money anyway since I dont have to buy the base BUT- I would really like to use the GM heads. I think the average power would be better and operating characteristics would have some benefit. Especially if I went HSR/MR over LTR with the T5. 6800 RPM 334 stroker? 375-400HP. All parts transferrable to a 383 later. I could live with that.

EDIT: This project idea is already looking grim.

Orr89RocZ

iTrader: (20)

Comp height will work just one way is either in hole or out of hole lol

You just mix and match numbers. Stroke/2 + rod length + piston comp height = total assembly length. Subtract from 9.025" standard deck tells you where you will sit in the hole. Zero deck of 9.000" should allow some flexibility.

Or use the gm 3.800" crank and 5.85 rods with those 1.25" pistons. It be even with zero deck block

TxTtopZ

I hear ya. Let me do some shopping and see what the numbers look like.

TxTtopZ

Ok, did some digging in old data I had... It's funny how much information you forget after learning it. I guess theres not enough room up there for cars I work on daily and my hobby... lol.

I have looked into piston sets and as usual, Orr was right on the money if I deck the block and use a 0.040ish gasket. (3.75/2+6.0+1.25) 9.0 block.

The heads are now a concern. I have not looked at Fast Burn stuff in a while and somehow forgot they are 210cc. I am now wondering if it's going to be too big?

Orr89RocZ

iTrader: (20)

6" rod is abit long for a 1.25" piston, but you get the idea.

TxTtopZ

What do you mean man there are a lot of 1.125" pistons for a 383 utilizing a 6" rod? I still can't believe you found those pistons for a 305!

InfernalVortex

iTrader: (4)

$830 for some 305 pistons? Ugh.

You can build a 383 for way less than that.

Damon

The other way you can go is to use regular flattop 305 pistons and the "shortie" 5.56" rods out of a 400. Keeps the cost down vs. oddball custom stuff. The shorties work just fine, though they do increase bore wear somewhat (which I suspect could be greatly offset by using modern pistons with an anti-friction coating on the skirts).

GM Fastburn heads are nice, but GM wants SOOOO much money for them and a set of good aftermarket heads will still equal or surpass them in power production. I haven't heard many people raving about them.

TxTtopZ

Yeah I agree those are way too high for a 305. I am still looking for a cheaper route. This is why most people kill this idea. Even though the concept is simple...

Cast SCAT stroker crank -
5.7 PM or nicer-6.0" Rods.
1.430 or 1.250 CH Hyper pistons or at least a cheaper forged. 3.766"

I mean come on people, this thread has been brought up over and over for at least 15 years. I know of ONE person who did it with the powerhouse kit and ran a 13.4 through a stock 700R4 with 081's and stockish TPI. Now I am seriously considering this option to be a stealth numbers matching restoration car with some ***** and I get crickets.

TxTtopZ

Most people wouldn't rave about them I suppose. The valves are smaller compared to what's out there. The only reason I am suggesting them is because of that reason. The Fast Burn's valve size will accommodate a smaller bore. The Vortec chamber will help with detonation.... Anyway... I am not opposed to using an iron vortec head, a TFS head, or reworked 113 casting

I WON'T however use a shorter rod for this. If you have to build it with possible issues down the road on a car that should be a cruiser, what's the point?

TxTtopZ

EDIT: Ive searched the internet for a solid 4 hours today and a few hours yesterday looking. Nothing affordable in a 1.250 or 1.430 compression height.

PROJECT BUSTED!!

InfernalVortex

iTrader: (4)

You can make a fast 305 with a big cam and heads. Not the most streetable but you can make plenty of power if you want. A 334 is still gonna be less streetable than a 350 at that power level so I imagine you had already resigned to that.

Damon

One last plug here for the shortie rods. As you've found, custom pistons are pricey. Standard 305 pistons aren't. Shortie rods were used very successfully by the factory in the 400 and that was in cars that came with warranties and such.

I built several 400s using shortie rods that did duty as street/strip weekend fun cars and for towing applications. One of those motors did service in 3 cars before I lost track of it. Unless you care about a little extra bore wear 100,000 miles down the road, there's no reason to shy away from using them.

For extended high RPM use (road racing) I would never recommend them. But for a cruiser where you're going to be driving around on the street at moderate RPMs most of the time and occasionally yawning the butterflies and taching it up, they work just peachy.

And they're the ONLY way you're going to get this project done at a price that doesn't immediately steer you into upgrading to a 350 (which is probably what most people should do anyway). Just that you seemed pretty set on doing a 334, so I offer it up for what it's worth.

TxTtopZ

Well it's just that I wanted to build the motor to my specific liking. One short cut here and one there ends up with something else than what you actually wanted...
I know of many cars that use "short" rods, and live just fine. I consider a short rod to be in the 1.4x to 1.5x range while normal or "contemporary" would be 1.6x to 1.7x and long to be 1.8x to 2.1x etc. and I totally agree I could get away with some 5.565" rods. Not only that but the shorter rod may also help in a few ways. But considering the engine is already going to be down on power, everything that helps I feel is even more critical. Lighter pistons, better wear characteristics meaning less drag, more dwell @ TDC and better combustion I think would be worth it. I have read two different takes on this matter.
Some reliable sources state use as long a rod as possible, others say its simply a means of connecting the crank and piston and should be one of the last things that matter when setting specific goals.

So honestly, I cannot draw any conclusion at this point other than the details rendered from scientific study, suggesting longer rod ratios are better. But where it's confusing is to what extent.... one over the other?

86LG4Bird

iTrader: (1)

And one MORE last plug here for the shortie rods.
Don't consider using them as a "short cut". I don't care how good you or your engine builder is, bore wear should be the least of your worries. There are EIGHTY other factors that will come into play with just about any non-factory build that will limit the life of the motor .....long before wearing the bores out

TxTtopZ

No worries fellas. I tried to do it the way I wanted. Things just didnt work out. This is the first time I SERIOUSLY was about to spend the cash for it. I've always been an advocate for the 305 as I believe it has the ability to take a TPI equipped car to 12's N/A with the right parts.

After ALL the up-to-date research, it certainly looks like the TFS heads with the better springs are a better deal. Last time I searched this was 2010. But the Vortecs by GM (I say that because I found out there are some differences in the Summit brand ones) with the compatible intake, matching valvesprings, machine work and all that, really is not any better than some aftermarket pieces... as you know.... This led to the demise of the whole idea. I thought I could get out relatively cheap.

I know you could do it on the cheap, but there are things I just wouldnt do.

Fast355

iTrader: (2)

Etec 170 heads would work GREAT on a 305.

Orr89RocZ

iTrader: (20)

I mean if you are looking for a 3.73-3.76 type bore piston and 6" rod 3.75" stroke for a 334, you need a piston thats 1.125-1.150" C.H.

383 6" rod uses same height but they are 4.030" bore. Not gonna work.

The CP pistons are 1.25" so they will stick out .100". Not what you want, but cometic may make you a .141 gasket


Custom build like that is gonna cost some money unfortunately

TxTtopZ

Yep. What I wanted to do was to keep the thing as close as possible to a 383 build for the sake of comparison science. Also for the formentioned reasons. The crank would have swapped, the rods would have if I could find pistons... So I was out a ring set and some pistons. The heads etc. all could have switched over and been fine after some porting. Oh well.

TxTtopZ

Do E-tecs require a vortec style base? If so you have just combined all the expenses of an aluminum head with running vortecs. Stuff aint cheap.

The other heads I thought about were the ZZ4 113's. Prices are OVER the TFS heads which show to flow better.

I also looked at EQ Shaver Vortecs and was not impressed all though the mags say they are a sweet deal.

Pistons.... This is THE problem.

Orr89RocZ

iTrader: (20)

Just take a hit on comp and shave the heads as much as you can. Angle mill them and intake

Fast355

iTrader: (2)

They have a vortec pattern and require a vortec base but crank out HP numbers that some larger port heads cannot touch. Saw a 10.5:1 355 dyno build make 485 HP with them. Seen a LT1 Impala SS run 1/2 second quicker in the 1/4 on a hotter day after swapping to the LT1 Performer aluminum heads (same chamber and ports as the Etec170s) My Express has a bolt-on, cam, head L31 350 that is putting down 374 RWHP through a 4L80E and 9.5" 14-bolt. Mercruiser Marine L31 port fuel injection intake, out of the box Etec 170s, 215/220 @ .050 comp roller cam 4* advanced, doug thorley tri-y headers, high flow cats and a long case magnaflow muffler.

TxTtopZ

No dude. That would make the heads dedicated to THAT motor and possibly render them useless for another build later. Trust me, I want to do it but I am not going to blow $1500.00 on a set of heads with machining that I cannot re-use.

I'd do the 5.565" stroker before that. Hell just leave it a 310ci for that matter.

TxTtopZ

Yeah, your still talking at least $1800.00 plus machining for a 305. For 1800 bucks I could have some AFR 205's ready for a 383 and probably money left over...

Come on guys, lets keep this constructive.

Orr89RocZ

iTrader: (20)

Well to be honest most heads that can fit a 305 which are 1.94-2.0" valve max wouldnt necessarily be good for any other bigger motor unless you leave it low rpm and mild cam. Waste of a 383. No less than 195-200 cc for a 383 imo lol. A 334 is more of a dedicated build imo.

Unless boost or spray is involved ofcourse

Fast355

iTrader: (2)

Not sure why you would be machining them for a 305? Use a 350 head gasket to match the chamber and DONE. You can get better than 9:1 compression out of a 305 with flat top pistons and a 64cc chamber. A 334 would be even easier to get compression out of. Other option is a .030" over 305, 64cc head for 9:1 compression and BOOST. With the right cam and a holley stealthram on those heads it would wrap to the moon as a 310.

Anthing over 195cc intake ports is a waste unless you have 400+ CID or run a 383 to 7,000+. On a 350 you really do not need any more than an efficient 180cc.

TxTtopZ

True there. I have seen what some 210cc Fast Burns can do on a 308ci via David Kauffung. That motor peaked at 6700?? 394hp IIRC.

Fast - I always value your input as you back 305's and somehow you manage to peak my interest with that Chester Van's powertrain. Hell all 3 of us like 305s. But I seriously think for an NA deal you would want 10:1 or more because your down some cubes... easy enough reason. That with an awesome chamber and longer stroke I think would make a killer street engine that's fun to drive. Building for boost isn't a bad idea but Street Lethal's build is already on top of that one.

I made this thread to see if a 305 stroker could be done with nice heads and intake for a reasonable cost. I seriously think I can beat 325hp/375ft lbs flywheel. I don't think I will get anywhere close to 356rwhp like you did. I don't know how you did that. I am trying to get close tho. I just need a 1.125" or 1.425 3.766" hypereucracktic (or decently priced forged) slugs.

Fast355

iTrader: (2)

Attention to detail in machine work and assembly and it was not exactly a cheap engine to build either. Keep the port sizes modest and the velocity high. Grind the cam with an early enough ICL to hold on to the limited cylinder pressure you can build, yet get the valve off the seat enough to move air through a restricted bored. Takes a well thought out and executed plan to make a 305 run hard.

I think his motor would have peaked earlier with a smaller port and likely made more power!!! My ZZ4 head 312 did VERY well at making power as well and propelled a very light 3rd gen like a rocketship.

Orr89RocZ

iTrader: (20)

Its not the port size its what you do with the air in the port. EMC is street rpm range but very racey parts, mainly valve motion from aggressive cam lobes. That emc motor made big average power. Port was worked over. I dont think it would have done what it did with anything less but hard to say since not many castings are out there with small valves