ignition problem need help

Motor I am running is running flat on top end and when reved up sounds flat on top end. Changed the ignition system and still have this issue. But the msd that was beening used I see that in the book does not say anything about a 16v system. Could the 16v battery becauseing the issue that is going on?

that would be fine with the MSD, you issue most likely is your valve springs.

Motor is new also carb is an older carb but was rebuilt put a 750 on it and sounds a lot better. Had an 850 on it. Seems to climb a lot more still sounds a little flat