Does anyone know the cc value of the stock dish piston on a vortec 5.7 block?

Trying to calculate the correct compression ration with a head change.

I believe this is the correct piston (for reference only--I plan to reuse the stock pistons.

https://www.rockauto.com/en/moreinfo...sn=994&jsn=994

 

Stock 4 VR pistons usually have about 5 - 6 cc of volume.

Trying to get any closer than that, given the tolerances in that as well as everything else, is a clearcut case of "measure with micrometer, mark with chalk, cut with axe".

Don't forget to account for deck clearance in your "calculation".

 

thanks! Figured the 4 valvevrelifes alone would be about 6 cc….then the dish on top of that. I thought it’d be more. Appreciate the info very much!

 

Pretty sure those motors are "flat tops" from the factory. No dish. Only deck clearance. But I could be wrong though.

Of course, don't forget to measure and include deck clearance in your "calculations".

Oh, maybe I forgot to mention; MEASURE THE DECK CLEARANCE and enter it into your "calculator" ACCURATELY. Without it, EVERY "calculator" will give you a "calculation" that's WILDLY WRONG for the physical motor you're working on.

What's YOUR short block's deck clearance? Do you know the factory "spec"? Do you know how much variation there is in production motors? Do you know what causes the variations?

 

Roughly 12cc dish on a L31 short block. Factory pistons were 0.023" down the bore. Factory head gasket is 4.060 x 0.028".

 

yup…those are the pistons!

I was using .025 in the hole as my deck clearance.