You are leading & jetting for the worst (knock prone) cylinder: smallest chamber with the sharpest exposed edges, least water circ to the plug and exhaust port, narrowest exhaust port.
Anything you do is only a test to be verified in the field. 50 is safe, 2,800 sounds safe until you know better, but RPM will finally depend on converter lock-up, stall speed, axle ratio. A really big engine turning 2,000 at 70 MPH might like all spark in already.


Boffin Emeritus