inneedofhelp

i have recently purchased an 86 vette, it has a very clean exterior and was told it had a blown head gasket, when tearing off the aluminum heads i see a chip from the number one cylinder missing and also the steam port gasket was not near the size for the block or heads. also the pistons are stamped.030, can anyone tell me if this is possibly a different motor such as a 400. The number stamped on the passenger side is 4888548. and the short block seems fine. what would be my best option as far as a rebuild? keeping the short block and buying new heads or going with a complete rebuild?

corvette_bob

Your pistons have ".030" on them? Seems like they might be a .030" oversize as used in a rebuilt engine. A 400 smallblock has a bore size of 4-1/8" (4.125"). A 350, 327, 302 use a 4" bore. So does a 383. To determine what displacement a 4" bore engine offers is done by rotating the crankshaft and measuring one piston's travel distance from top to bottom of its stroke. 3" is a 302, 3.25" is a 327, 3.48" is a 350, 3.75" is a 383. if you have a 400 block, again the bore is 4.125" w/ a stroke of 3.75". If that stroke is shorter, like 3.48", then you've got a 383 again, but done using a 400 block w/ 350 crank. Your .030 pistons will slightly increase the actual displacements I've listed, but I think you get the idea.

A95Y

Need to find the correct number first.

http://www.chuckschevytruckpages.com/casting.html

haljr

86 corvette OEM numbers:
head #462624, 350ci, 230hp, iron heads or
head #14101128, 350ci, 235hp, alum heads
block #14088548

also check this pdf for all 86 stuff:

https://www.gmheritagecenter.com/doc...t-Corvette.pdf


for the rest - like bob said

ghoastrider1

like bob said, its a .30 over bore. That was done eitherto refresh the engine or turn it into a 383. like bob said, you gotta measure the stroke now to see whatcha got.