Hi Mike,
I have a 73 US bike mag with article by RC tuning a big Four.
Quite good, but I don't think he gave to much away.
Pics of his pistons show two left and two right handed pistons with offset valve recesses.
That was the reason I asked you about the Wiseco recesses being in line front to back, and all pistons the same.
Sorted now, and have you checked your email.
Thread drift over. You should have seen some of the bikes I had years ago. You would'nt be seen dead on one now, but then I thought they where great. Passed my test on a Monkey Bike in 63, but that was a bit special.