I have a 2.8 stroke is 2.99, if i put a 3.1 crank in it, stroke is 3.31. Will the pistons hit the heads, if not could someone explain why they wont. I am confused. Thanks

-William

 

Which pistons will you be using? If you use the pistons for the 3.1 they won't hit the head. If you use the pistons from the 2.8, they will. Why?

The deck heights for both block are the same, as are the connecting rods. The difference in crank stroke is 3.31-2.99 = .32". The distance that the 3.1 crank pushes the end if the connecting rod is .16" higher relative to the deck surface (compared to the 2.8 crank), so the wrist pin must sit higher in the piston to compensate. The 2.8 and 3.1 pistons are the same diameter, but the wrist pins are set at different heights.

 

what is the deck height, piston top volume, and gasket height? if i have 53cc heads what would they be after shaving .050 off of them?

 

Deck hight is the distance from the crank shaft center line up the middle of the bore to the blocks deck, on a 2.8-3.4 it is 8.819''.
The piston volume is the - or + cc that the piston has more of a dish it is - cc if it has a dome it is + cc or it could be flat to 0cc, 2.8-3.4 pistons in a camaro are - 3cc to -5cc.
You gasket height is how thick your cylinder head gasket is.
I don't know how many cc's you would lose if you milled the heads .050''. Usaly people mill them .010'' to .020'' at a time.
If you put the engine together with 2.8 pistons and a 3.4 crank the pistins would stick 3/32'' above the deck, when they should sit .025'' or less under the deck.

 

if youre gonna tear it down that much you may as well get lighter pstons. the 3.1's are heavy and the 2.8's are even heavier