I picked up a 327 in great condition recently. It has been rebuilt very recently and the internals look great. My concern was if there is any way to identify what kind of pistons are installed in it. I am aiming
for ~400hp at the crank, which means I expect about 300.. but i want to be sure the pistons installed can handle what I am aiming for.

thanks!

 

what are you aiming for? ie...induction? N/a or forced? N2O?

 

N/A... but going for decent compression.. thinking 11:1 +/- .5 may be in the works... n20 is a no go and anything forced simply wont fit under the hood.. so all natural.

 

Pull a spark plug and look in the hole when a piston is at TDC. That will give you an idea about what pistons are in there.
Get the casting number off the heads, that will help ID what the compression ratio is. I think 11:1 is pretty optimistic, unless you're going to swap in dome pistons and small heads.

If this engine is complete, I would hazard a complete WAG of about 8.3:1 CR. Anyone wanna take my wager ?

 

Good luck with that spark plug hole suggestion.

Any pistons in good shape can handle that much power - cast, hyper, or forged.

To get any sort of accurate compression ratio you would probably need to pull a head to measure deck clearance and see if the are flat-tops or domed.

 

the heads are off.. no casting numbers on the face, very shallow valve reliefs, flat top.. heads im most likely using are 58cc..

 

Like I posted earlier, any pistons should support that power level, as far as reliability. I would say your compression ration will be more than the WAG of 8.3, and less than your hope of 11:1. If the heads you mentioned are GM castings of some sort, I would say that will be your biggest hurdle as far as 400 hp out of a 327.

 

ah, ok, flat tops will make it higher. The casting numbers are up inbetween the rocker studs.
Check which heads they are, then we can give you a hint. Also bring the pistons to TDC and measure the deck height.