My 360 has a Howards flat tappet with 1.6 rockers, Currently I have a Crane dual spring, 150lbs on the seat and around 400 open. My camshaft is a little bigger though, from memory it was around 0.690" valve lift and 266-276 @ 0.050"
It makes peak power at 6900 RPM, turns to over 7000
