[strictlypersonl]

If your engine (cam, probably) needs breaking in at 2200 rpm for a prolonged period, I would augment the engine fan with an external one. You're generating more heat than usual, first from the higher rpm, second from what is most likely a tight engine.

Your tach should work OK with a wire directly from the MSD tach output to the signal side (not the green-wire side) of the tachometer.