Any stovebolt engine, 216 or 235, can have more compression by shaving the head, with maybe the exception of those early domed-piston engines. However, there's a problem. Unless the intake valves are sunk deep into the head the same distance the head is shaved, the valves will hit the pistons. Then the geometry of the pushrods and rocker arms is wrong, and lots of monkey motion is involved in getting it back close to right. A 1954-56 head that was used prior to the 848 can be milled .090" to get the same compression ratio as an 848, but the valve depth must be altered to prevent crashing them into the pistons. I assume an 848 head could also be milled to raise the C.R. as long as the valve interference was corrected at the same time.
Jerry
