The 216 engine block is about 3 MM shorter than the 235. The taller block is how Chevy chose to compensate for the longer stroke 235 crankshaft, rather than manufacture a shorter connecting rod. The 292 rod should prevent the 235 piston from sticking out of the top of the block, but the piston can be machined a little if necessary. The intake valve will be the only one to be concerned with for clearance purposes- - - - -the angle of the exhaust valve makes it virtually impossible for it to touch a piston. The quick and easy way to check piston/valve clearance is to place a small piece of sculptor's clay on top of the piston, assemble the engine temporarily, adjust the valve clearance, and rotate the crankshaft at least twice. Remove the head and measure how far the clay has been compressed. You should have a minimum of 1.5MM clearance or a little more between the piston and the valve at the closest point. Good luck!
Jerry
