Good point Lelo thanks. To verify this I should be able to measure center of stem to center of stem on "assembled" heads with different valve sizes correct? Measurement should be the same?
I measured valves still on 4027163 heads and got approx 1.5005" EX and 1.7785 INT
Another set of valves on heads #3671587 gave me approx 1.60" EX and 1.8805" INT