I’m looking around Craig’s list for a B-20 engine to rebuild and stick in my PV544. As far as the cyl. heads go, which stock head has the largest valves? While I will be using carbs, and a header, I wonder if any one here knows the difference between the B-20 a, b, e, and f cylinder heads and or blocks? I only played with B-18’s back in the day. I’m not going for an all out race engine, though the 2.3 and 2.5 stroker cranks look cool.