NO on Oldsmobile. there are two different deck hieghts for Olds. Small block 260,330,350,403 cu in, all used the short deck and the same stroke 3.38.
Big Block 400 425 455 were taller and used either a 3.975 or 4.25 stroke 400 used both! 68 69 used the the 455's 4.25 stroke. Heads from either will bolt on either but are different in chamber sizes etc. INTAKES are wider on the big block