Piston types. Dumb queston but i'm, askin anyway

[Broken_down?]

been looking recently for a complete engine rebuild for our 350. I understand everything in the kit except it ask what type of piston style. It lists: Flat, Dome, Dish. Which of the 3 is best and why for a stock build.

thanks

[turbochevy]

just depends on what you are looking for.....
what are your plans for the truck?

[Broken_down?]

My plan is to restore her back to complete factory. Everything!

If I get my way and find 327 somewhere then I will drop that back in and restore it back to factory. As it sits the truck is a 68 with a 71 350. I so want to get rid of this 350 and put a 327 back in. But no one around here sells the 327...

[Billla]

There's not one that's "best" - they're means to get different CR, with dished pistons giving the lowest CR and domed the highest. If you check the kit listing, it will give the CR with each set - probably based on a 64cc chamber.

[Myself]

At 76cc or 64cc chamber volume, either way, the flat-tops will be a good choice for stock to mild performance builds. Won't cause any detonation problems.

[Robznob11]

yes go with the flat tops, most all sbc heads have small chambers 64-76 some after market heads are even 54cc so with that in mind unless you want to run race gas domes are out of the question not to mention you have clearance issues, no then with the dish you will give up an optimun compression ratio and you motor will not likley exceed 260 hp. flat tops are the best choice becuase you can get about 9-10 to 1 comp ratio witch will work well with all mild tricks you want to add later like cams etc. they also work best if you want to bump them with a small bit of n2o. there are 2 different types of flat tops some with 2 valve reliefe and some with 4 i like the 2 so that you dont give up that extra crunch. also with the flat tops you can fool around with head gaskets to alter your comp ratio and go from mild to wild but thats all the secreats im gonna tell you so good luck...

[ETsC10]

Broken Down,
I've rebuilt a 327 (still on the engine stand), for my C-10, using forged flattops and a mild RV cam (268). With what I've chosen I think I can get away with regular gas; just barely. The large journal 327 cores are still out there but, being a 2 year only, they are scarce. Plus there are a bazillion Corvette owners looking for the same block. Good luck! ET

[Billla]

Originally Posted by Robznob11

also with the flat tops you can fool around with head gaskets to alter your comp ratio and go from mild to wild but thats all the secreats im gonna tell you so good luck...

Gaskets vary a bit around .040...you're not going to go from "mild to wild" with that

[crazy longhorn]

Im not here to talk too much about compression, but more about Quench. No IMO , a 327 or 350 should be set up with a 2 valve releief flattop to keep the compression up on a good street motor.....but... You also want the comp ratio to reflect proper Quench (piston to head clearance), & that should be in the .040-.045 range, with a .035 minimum for steel rods running under 6500 rpms. the tighter you can cut that quench, the more compression you can run without detonating that pig! Also, the more timing you can run without detonation.....ei , a 10 to 1 mill(with proper quench) will run better, with less detonation,& more timing than a 9.5 to 1 mill that has too much quench distance! That is why gasket thickness should not set the comp ratio Now you can "fudge" on the comp ratio, by running a hotter cam,(static comp ratio vs dynamic comp ratio) or aluminum heads.....they loose a lot of heat, & will allow higher ratios(lots of debate there, but generally 10.5 to 11 to1 on alum heads works). best of luck..... L

[Billla]

No pushback on quench, other than the very careful machine work it takes to get there. Deck height on a stock block varies GREATLY, and it can take an .025 cut or more to get zero deck...which can affect valve train geometry and require a cut from the manifolds. At that point, you also need to ensure the block is not just decked, but squared as well...so we're starting to talk about $1K in machine work here

Just don't get confused about what you're building...you just don't need to go anywhere near this wild (or spend this much money to get 300+ HP from 355 CID.

[crazy longhorn]

Originally Posted by Billla

No pushback on quench, other than the very careful machine work it takes to get there. Deck height on a stock block varies GREATLY, and it can take an .025 cut or more to get zero deck...which can affect valve train geometry and require a cut from the manifolds. At that point, you also need to ensure the block is not just decked, but squared as well...so we're starting to talk about $1K in machine work here

Just don't get confused about what you're building...you just don't need to go anywhere near this wild (or spend this much money to get 300+ HP from 355 CID.

I built a bunch of them with stock decks, chitty quench, ect & will say you will do fine for the run of the mill streeter.....BUT THERE IS MORE! for an extra buck 50 - 2 bills in machine work, you can have something that just "tunes" sharper than the next dudes toy.....then again, if you dont crank it up & race it from time to time.....nobody will know the diff!

[Robznob11]

well you can actuall get head gaskets in copper down to 15 thousands.. we took a 350 bought flat top piston rebuild kit from paw for 159$ decked the block down to zero and made a clean up pass on some 64cc heads. used some copper gaskets and ended up with 12.8 to 1 comp need less to say with about 1000 dollar engine we stomped some seriuous low 12 second big block cars and we had our rev limiter set at 5000. it was not even a compition we then took this s10 to the strip to find out it would run 11.35 in the quarter shifting at 5900. if you know how you can make hp with what you got....

[BCOWANWHEELS]

Aa 1971 350 Is A Excellent Engine. The Best Yr Of The 350,s Is 1970 & 1971. Most Likely You Got A Set Of 461 Heads, Steel Crank, Hi Nickel & Tin Block. If It Was Mine It Would Take 1000.00 To Buy It As A Rebuildable Core. You Know There 300 Hp Stock Right ? Just Build It Back Completely Stock Except Install Hard Valve Sets On The Exhaust Ports Of The Heads.
Bob