Quote Originally Posted by weylinthedirty
Ok thankz.. Do you mean the Diameter of the piston bore?
I know for a 350 its 4" so if its smaller than 4" its probably a 305?
yep. if it's smaller, also check the stroke by measuring from BDC to TDC, you can do it with a dowel in the spark plug hole if the heads are on, mark for BDC then bring it to TDC and mark, set next to a ruler and check. 305/350's are 3.48 " stroke, 267's are also but it rules out the 265-327's as they all used diffrent strokes.