I am looking for someone familiar with the 248 cylinder head to do some head work and porting. I believe that the intake valves can be enlarged slightly by cutting down the diameter of some big block chevy exhaust valves and installing narrow, hardened seats. I can have this done locally but would like someone with experience to port the head so that I get better flow w/o sacrificing reliability. I've heard that the port walls are somewhat thin so I'm concerned that a novice may go too far and the head will crack.

In the California Bill's Speed Manual (1954) they claim that you can enlarge the port to the same diameter as the O.D. of the manifold guide collar. I haven't personally tried this, as I concentrated my efforts on the bowl area, which seemed to have a lot of extra meat (320 engine).