Big Block Tunnel Ram 660s Questions

Sorry I missed that . And IIRC the MSD unit is adjustable for total amount of advance but not when it starts . In which case you could lower your initial timing and recurve the distributor to compensate .
I have the bushings for 20⁰ mechanical and the springs set to bring it in about 2200. With initial timing of 18⁰. Maybe it should be dialed back to reduce idle speed, but I thought you should use as much as the engine wanted without ping or detonation.