Hey Guys,

I have been doing some research on this build up and I noticed the CNC 345 version of these -1 heads it recommends a 4.375 bore. Why is that? Will the valves contact the cylinders? Would this hold true for any -1 with a 2.25 valve? My setup has a 4.350 bore. I don't need the 345's but I have seen a few sets of heads available but they all seem to have big valves.

Thanks!