that head 3695451, could be found commonly on top of blocks 3695408 and 3835814, short side cover 216s
the intake manifold bolt spacing for the carburetor is 2-3/4 inches for a 216, so unless someone mix/matched parts, if your carb bolts are that spacing and not a full 3 inches then you likely have a 216 block
pull out one of the push rods, the 216 vs 235 are different lengths, the 235 got the majority of it's extra displacement with stroke increase, and so it needed longer push rods
the piston diameter increase was only 0.062 inch
-s
