Reborn756

Thanks for the quick reply rb85TA!

So these pistons would be ok then? I just got back from visiting my Uncle, and we talked for a while about this whole thing. I showed him the pistons and he said that he had problems with Hypereutectic pistons holding up under high horsepower applications. Has anyone had this problem before? and will they hold up in my application, considering I'll only be building this motor to run between 400 to 500 horse? Not saying I'll get those numbers with this, but that's the max range I'm aiming for.

We also talked about the heads. He said they're a good design that's worked for years (I knew this from some hotrod forums I was on) but he also said that a smaller combustion chamber is going to run better (just like all of you guys have been saying). The one thing he said was to get pre-assembled heads, because price wise they just make more sense. Does anyone know of good pre-assembled heads with smaller chambers, that are still priced good? These heads I'm looking at are only 350 bucks a head. That's why I've been trying to figure out how to raise compression without changing them.

rb85TA

Really don't like pre assembled head's, reason is they are put together with cheaper "economy" parts, you can get a set of bare head's cheap ( $4-$500), then shop & get the rest. You'll have a little more in them, but you know what you got!
Piston, if you're even slightly thinking 450+, I would NOT run hyperuetec pistons, under 450 & ok.... probe pistons ( not top of the line, but decent price & quality ) about $400 +\- but they're forged & will handle 5-600 hp & a small shot of N2o.
Simply put, Speed cost $$$..... HOW FAST DO YOU WANT TO GO?
Hope this helps

rb85TA

If you decide to get a set of bare head's, I'm pretty sure that I have a new set of Manley race flo valves 2.08/1.60 11/32's stem & +.100 long that I don't need. Let me know

Reborn756

Definitely rb85TA, thanks a lot!

What brand of head do you usually go with? My uncle told me he usually goes with dart heads on mild performance engines, but I've heard some bad things about dart recently. I'll take a look at these probe pistons and see what I figure up. the hypereutectics will hold up under 450 horse though? if that's the case, I might still go that route. Pushing this motor over 400 seems like it's going to be a job in itself and might not happen.

rb85TA

To me, for the minimum price difference & the age old ,never ending search for more power. . I will always go with a forged piston. Even if you never reach that point, you'll never have to worry about them.
If you do the math, realistically. .. you're going to have $1200.00 in a set of head's (bare +parts & assembly ), for that amount you can get a really good set of PRO-FILER head's, that are capable of great power out of the box & have the ability to grow with you ( very porting friendly ).
There are a freaking ton of cheap crap head's out there, but I would rather see you go with a decent quality, that will last. .. over saving a few dollars now ( and that savings goes away the first time the "cheaper " stuff fails ).
Look up PRO-FILER HEAD'S, great people to deal with.
If you are going to buy an assembled head Dart, Brodix & AFR, also come to mind ( but even they use budget parts on they're cheaper packages ), & the price will jump to $1,500 +

Reborn756

Alright, thanks a lot rb85TA! I'm going to sit down and figure up prices for the heads I'm looking at, the pre-assembled heads from either brodix and AFR (according to what I read, Dart makes the heads I'm looking at for summit) And then these Pro-filer heads you mentioned. I'm also going to break out the desktop dyno and toss these all together.

Also, I have a question regarding the desktop dyno. When inputting head information, it asks for average port diameter and port length, in inches. Is there some place I can find that information?

rb85TA

I'm only trying to prevent you from suffering the way I & many others have in the past.
I bought a set of procomp head's (bare ), bought all good parts, took them to the machine shop & BAM!!!! $1034.00 to fix all of the problems & assemble them. If I would have listened to the same advice. ... I could've bought one badass set of head's for less!
Just sayin

rb85TA

You might be able to get that information online, several people have tested these head's for accuracy of flow numbers. But the generic would be gaskets , fel-pro, mr. Gasket, etc.. will give intake port opening measurements, like 1.31x 2.00 ( example ).

Reborn756

Thanks for the info. I'm going to toss all this together and see what the dyno spits out.

That's one thing my uncle's preached to me through this whole process. Don't cheap out and lose quality, because you'll get screwed twice. Once by the part maker, once by the machine shop to fix the part maker's mistakes

cardo0

Just a couple of comments on hyper pistons here. I believe they are velocity/speed limited. If i come across a rpm number for your 3.75" stroker ill post it. But the smaller bore should mean reduced weight and require less strength so my guess is below 500hp and 6000rpm hyper pistons would survive. But forged pistons are better insurance.

For heads u need a dummy head to size up on the block/bore to ensure the vlvs clear. My recommendation would be a "ported" L98 head. Several vendors sell the L98 head ported with better vlvs and springs as a budget sbc head upgrade. The small 58cc head chambers should make plenty of compression. Try TPIS and Lingenfelter for those L98 (once u find they fit). Or u may some already ported used L98 heads.

rb85TA

Yeah, building 302 cubic inches, also means that you don't have to have a monster set of head's. But, having a set that fit this build & be able ( with porting & valve size upgrade ), grow/work with the next bill . ... to me , is worth the few dollars now vs. another set of head's later.

rb85TA

Build! Not bill. . LOL! Freaking auto-spelling P.O.S.

Reborn756

Thanks for the info guys!

So Cardo0, I should just go for a set of L98 heads then? This should work out fine, considering I want to use an L98 block for this. I'll look into a set and see what I can get them for price wise. Thanks folks!

Edit: It looks like with my head/piston/gasket combo, the L98 head will give me TOO MUCH compression! 11.6:1 compression ratio with 0 decking O.O

What volume pistons and what thickness gasket would you guys suggest if I went the L98 route? I don't know how much Blue 112 is per gallon right now, but my guess is it's not $2.30 a gallon!

Reborn756

For anyone interested in this, I did some research on Hypereutectic pistons.

It turns out that they can handle high horsepower (750 was the highest so far I've read about), and they can handle high rpms (highest I've read so far was ~7000 RPM). They will last for a long time if the engine is tuned right and the pistons are installed according to manufacturer's instructions. Hell, I've even read about a guy using the cheap summit set I saw at 12:1 compression and with nitrous injection! What they can't handle is any sort of detonation. The slightest bit of detonation and hypereutectic pistons will break. Sometimes it's just the top of the piston and won't cause too much damage. Sometimes the piston likes to make it's own exit hole through the block.

To sum up everything I've learned so far, Hypereutectic pistons are good for tuned street applications with no chance of detonation. They'll handle racing applications, but you better make damn sure you pray to every god in the book every time you run it.

cardo0

Well u really dont know final c.r. until u measure it and u need the pistons and heads to do that. But u can estimate what parts u need for your desired c.r.. What im saying if u have an idea of what head u will use u need to shop for pistons to match the compression ratio for the range of cam u choose. Always buy the cam last as thats the easiest part to customize and cheaper also.

Now u need a dummy head of the type u plan to use to place on the block and snug down finger tight with bolts. Then u can reach up inside the bore and scribe a mark all the way around the circumference of the bore. Now remove the head and see if any of the scribe mark enters the chamber rather than the flat quench area of the head. Also see if the vlvs clear the scribe mark. If any of the scribe mark enters the chamber area u really shouldnt use that head. Well your choices are limited so it shouldnt take long to decide. But u can choose pistons much easier than heads to get the correct c.r. u need/want.

Remember your an enthusiast and have to buy parts as they sit on the shelf - nothing much custom on a hobbyist budget.
BTW u could easily handle 10.5:1 c.r. w/alum heads.

rb85TA

Well, you read all kinds of stories. ... people can & will tell you all kinds of stories (that ,at least in their minds, makes them and/or their car seem to be badass). I.e., John runs 11.20's @ the track. .. & I beat him by 3 lengths, so my car's gotta be running low 10's..... ahh hah.
Magazine's are guilty of it too, Hot rod did an article about my school & the build we were doing on a 98 camaro Ls1 /6 spd car.... the article said it was running 10.40's & getting 26 mpg, but we hadn't got there yet, it was like 11.20's & 24 mpg! The owner of the school questioned the editor & he basically said that their interpretation sounded better.
So, please, when reading this stuff take it with a grain of salt.
I've seen hyperuetec pistons crystallize under N2o, some turned to dust, some the rods rip the pins out of & some go the distance.
Yes, proper tune comes into play, but that's true with all engines, proper use of the engine as well, if you're building an engine to make power to 6000 rpm & everything in the engine is picked to be used at that rpm & no more. ... but the engine just work's better than it should & pulls to 7000? You either set the rev limiter @ 6000-6200 or you tear it down and buy/use parts that will live @ 7000. Unless your rich and have more money to burn.
Like I told you, build a rock solid bottom end, buy a decent head that you can use not only on this build, but can grow with you & your future needs. If you choose to do it this way you will spend more money now, but a HELL OF A LOT LESS IN THE FUTURE, THAN YOU WILL IF YOU DON'T.
It's your car, your engine & your money.... no one here can make you do it right, that's on you.
Good luck with it & I truly hope that you get what you want out of it.

Reborn756

Thanks for the reply rb85TA

I'm definitely not going to trust 'em. I just thought the info was interesting. 11.20s at 24mpg? Damn.

I'm definitely going the forged route, probably with Probe like you suggested. The next thing is the con rods. The L99 con rods are PM rods, and I don't know if I like that. If I'm going forged pistons, I might as well go forged rods too. The only problem is forged 5.94" rods are very rare and very expensive. I'm going to see what other rod/piston combos I can come up with that will put the piston where I want it.

I think I found a set of heads I like. Trick Flow makes a bare aluminum head called a Super 23 195. They claim to be fast as cast, have a 195cc intake and 75cc exhaust, thick walls for better porting, and best of all (for my situation), only a 62cc combustion chamber. And they're still fairly cheap ($450 for the bare head)

aliceempire

iTrader: (14)

L99 rods are just longer LT1 rods. Other than a tiny dot and the length they look identical too LT1's. And again I have a set here. They hold up really well. Best of the factory stuff. Resized and good rod bolts and you shouldn't have any problems depending on how much power you have in the end. If you're going for big enough power to need a full forged bottom end, you'd be spending ALOT more money on a 302 than a similar 350. You'll end up needing either custom rods or custom pistons. Crank isn't cheap either. About ten years ago I did the homework you're doing now. I think you can get srp pistons for a 302, but compression is high (11:1ish) unless you go to larger chambers.

Reborn756

Thanks for the reply aliceempire!

My goal is 400hp and 400 ft lbs of torque. I'd like to keep torque at 350 at the bottom end. I'd hope they'd hold up to that (I read from Chevy performance they were rated to 500 hp).

Thinking about selling those rods anytime soon?

rb85TA

They're are a ton of 6" forged rods on the market (tjat's .06 longer than the stock rods, which is nothing. .). as a matter of a fact that reduces the amount you have to have the deck cut.
There's nothing wrong with Trickflo, but $450 a head , ....means $900 bare + valves +seals +spring locators +springs +retainers+locks+ valve job & having springs "stacked". It's not a bad thing, please don't get me wrong. ... ( I am one of the guys that mentioned it previously ), just wanna make sure you have the full picture. Did you look at pro-filer?
I can help you out with a good set of lite-weight (505 grms ) 6" rods bushed for floating pins, I also have a set of valves i previously mentioned ( I paid good $$$ for my parts, not TOP TIER, but NOT scrapping the bottom of the barrel either ), I can help you out at a loss but not free. Let me know

rb85TA

Just so you know, I'm not a parts seller anywhere & I'm not trying to unload junk used parts either. The stuff I have, I bought for me & are new in original boxes. I changed the direction of my own project's & don't need them. If your not interested, that's fine too, they're paid for on my end & I'll use them eventually. ... or hook up a friend or family member ☺, so no worries. Just trying to help & I think that they would fit your build nicely.

Reborn756

Sounds like I'm going with a 6" rod then. And I could probably get a good set for about as much as the L99 pm rods would cost.

Those pro-filer heads are only 475 a head, and you can have them add in valves, springs and retainers for a nominal fee too. They sound like winners to me!

The question is now, which set would be the best for my application? I was thinking the 23 degree head with 64cc chamber, angled plug , 2.020 intake and 1.600 exhaust with standard coolant passages would be a good fit.

I also like the All American branding. You don't see too much of that at reasonable prices anymore.

Edit: That's the 195cc intake head. Forgot to include that. I'd definitely be interested in those parts rb85TA. I just need to get the budget together and wait for the "boss" to give me the go ahead to start buying stuff.

rb85TA

LOL! I heard that , pro-filer has a 185 cc head I believe, just give them a call (very easy to deal with & will make solid recommendations for your application ). Next will be figuring out best cam choice ( after, you know exactly what head & piston your running ).

aliceempire

iTrader: (14)

I would never say .06 is nothing with any engine measurement. Factory sbc deck height it 9.025...if zero decked is 9.00 where would you fit .06? Not trying to be snippy, just trying to have my math right.

rb85TA

Ok Alice, step away .... from the buffet!
Had too sorry lol, any way. .. zero deck is not a set deck height of 9.000" it's what ever the rotating assembly measures, in this case if my memory serves me correct, will be 9.06"

aliceempire

iTrader: (14)

It'll boil down to what the actual block's deck height is and what the compression height is on available pistons. That's where custom pistons may come in to order, to prevent from pushing the piston past the deck.

aliceempire

iTrader: (14)

Also 9.060 is taller than 9.025

rb85TA

I'm sorry, typo 9.006".
Anyways, the deck can vary from the factory 9.010-9.025 & yes you need to have the block, crank, rods & pistons to check actual deck of the block. Their is no actual tool available to check deck height, people make their own. .. but most shop's just put the rotating assembly in and check actual deck.
You should try to find an original low mileage truck or car for the donor ( gives best chance of finding an uncut block, unless you buy new).

rb85TA

Also, it is possible & has successfully been done, that you can run an engine with the piston comes out of the cylinder a few thousand ( say you have a cut block that was zero decked for previous build & piston of new combo protrudes .006 , your run a .045 compressed height gasket. .. it leaves you as if a zero deck & .039 c.h gasket).

rb85TA

Aliceempire, ya know I was just poking fun at you, no real insult intended .

aliceempire

iTrader: (14)

No insult taken. Just pointing out how FAR .06 is to move a piston out with the connecting rod. It may not be doable without custom pistons.

rb85TA

Well, I finally broke out the calculator. ... with a 3" stroke, an off the shelf 350 piston (1.425" c.h.) & a 6.100" rod ( I stand corrected, sorry not trying to mislead anyone ), it puts you at zero deck with a 9.025" std. Deck block.
So, the 6" rods I have won't help, but Scat makes their pro competition rod in a 6.100" &they're about $360-$375 on eBay ( that is cheaper than I could sell you my 6" rods... bonus for ya ).

rb85TA

Or as aliceempire points out... a custom piston ( which blows up a budget build).

cardo0

Reborn i dont see u saving any money here. Your original idea of using the 5.94" rods and LT1 pistons for pocket change has become forged pieces using custom rods. Hey buddy this should be and experiment not something to spend for a dream build. I liked the idea of powder metal rods with the crank they came on and hyper pistons also. Throw on a set of reworked L98 heads for high compression that supports a big azz cam and have fun with your hard earned $$$ still in the bank.


Going fast dont have to make u poor.

rb85TA

The 6.100" rods are not custom, they're for an Ls1 but instead of PM rods, they're forged & he can get them cheaper than the scat's I mentioned. .. but the $80-100 for a better profile & a company that stands behind their products. ... it's worth it to me.
Reborn knows he can do it either way, it's his & his $$$. I've just told him , ( as has his friends & family & others ), that if it's worth doing, then it's worth doing right.
I'm not trying to get him to spend $10,000.00 to make 4-500 hp, but trying to help him make his money count. Besides, it may sound cool to a few people, that he managed to cobble together a 302 from leftover used parts from here and there... but, to anyone that might be interested in buying his car ( as he has mentioned, after he's done playing with it), it wouldn't be a strong selling point. On the other hand, a responsible build (new parts & quality machine work ), will /can make /sale, for more money.
It's all in one's perception

Fast355

iTrader: (2)

^^^^PM rods are ALOT stronger than people give them credit to be. I have a factory L31 4-bolt main shortblock in my 1997 Express. ~380-400 hp on the engine, was shifting 6,100-6,200 rpm on a 6,500 rpm revlimit with the old cam and Etec 170 heads and ran 6,500 numerous times. It has had ~20 bottles of nitrous run through it at 75 to 125 hp.

Short Stroke + Long Rods = Very rigid lower end with low piston speeds and alot of strength. Just look at what the 4.8 guys are doing with stock PM rods and cast crank.

rb85TA

How much does a new set of PM rods cost?

Fast355

iTrader: (2)

No idea on if you can even buy new 5.94" rods or the 3" stroke crank these days but there was a time GM was selling L99 crate engines complete for $700 retail.

rb85TA

Ya know those days are long gone LOL! So how much to buy a reconditioned set ?
I ask because they're "cheap" 6.100" rods on eBay ($260-$375) & they're forged.
Like I said, it doesn't matter to me which way reborn goes with his build. But, I am trying to help him. He has stated that he plans on building the car, driving / playing with it for a while. ... then selling it. So, if you're looking for a thirdgen & come across his add & read that it has a 302 cid sbc in it & the price seems right. You're going to call & ask a few questions, like. .. did you mean a 305 sbc? He says no sir, it is an actual 302.... I built it for the car to mimic the 67-69 DZ302, but I used modern parts. Then (more than likely you're gonna ask something like ), how did you do that?
Are you really going to be pleased with, I bought some reconditioned powder metal rods, a used cast crank that I had turned at the local machine shop & a set of hyperuetec claimer pistons. .... & YOU'RE REALLY GONNA SAY, HELL YEAH I GOTTA HAVE THAT?
I wouldn't. But , if he tells you that he bought a forged 3" stroke crank, 6.100" rods & pistons new & had it balanced and assembled ,then topped it off with a decent set of head's, intake & carb. ... yeah, I would really consider that as a good buy... just sayin. And definitely just my opinion.

cardo0

Well u may think spending more on better parts is a better value but something Reborn has to be honest with himself is has he ever rebuilt a sbc before let alone one that lived. Not trying to bust someones bubble but i read most first time builds are failures more than successes. Having built just a few engines myself my advice to anyone building their first try to spend as little as possible. Just to many things to go wrong with all the tight tolerances and measurements that are needed. Crank & rod brgs, thrust, piston to cyl wall, ring gap, oil pump to pan, sometimes vlv to piston, bolts torques all need to be correct and all seals need to be installed correctly. And how many times has cheap machine work led to failure even with good assembly. I read owners that rebuilt the motor and didnt even know how to spike the distributor. How many engines died before the engine and cam was broken in? Ill bet plenty more than owners that will admit to it. How many owners with a failed rebuild fess up to it? We will never truely know that.

Like i said before, dont waste money on an experiment. U dont need expensive parts to go fast. Hey its a sbc and plenty of go fast cheap parts are on the shelf or in the junkyard.

rb85TA

Ya know, I think I've said it, you've said it, hell even reborn has said it..... it's his engine build.
I've put my 2cents in & so have you, other's as well, let's leave the direction of his build to him.
Besides, he grew up in the garage with his dad & uncle .... he's got plenty of hands on help.

cardo0

Yea i dont want to tell him or anyone how to build or what to build. Just want to share what i learned and observed over the years 'bout the sbc and hope that can help. But im sure Reborn has some good advice right at home to.
And i bet they remember the days with 283" in a tri 5 chevy could pull 8000rpm with a moderate lift solid lifter cam and stock stamped steel rocker arms. Small motor in a heavy car but near 8000rpm it would still be a lot of fun. Im sure a 5liter 3rd gen at 8000rpm would be even more fun than that.

rb85TA

Yeah, I think it's cool to. Not everyone gets it, but. ..it ain't theirs!
We all tried to convince Reborn to go bigger, but, that's not what he wants. ... I myself have thought about building one, but based on a 283 crank & an early 327 sj block all forged internals, massive solid roller cam, badass set of head's, single plain intake & about 850cfm carb...then spinning it to the moon! .... but I've yielded to the torque monster, building a 422cid for my ride.