Mine is a nice apparently low mile K4 engine, I'm going with a ported head , valve job, milled .010, E-Bay 836 kit, K0 carbs, F timing advancer, and for now a rough looking header I think is a jardine. I may try to modify a stock F2 header to fit a K later.
The goal is a good street performance, short trip, fun to ride and look at bike. 1970's appearing resto-mod K0. It has to sound awesome and be reasonably fast although I may do a quarter mile just for fun, I won't be racing anyone. I want a nice cam but not one that's hard to live with long term. The two my brother have are large x huge, not sure they are what I would want. The previously mentioned RC315 and Ken Harmon F grind.