Alright, so I have a 77 Datsun b210 and I am trying to fix the timing. The Carb is backfiring (like a gunshot) and I think that means the timing is too advanced. The car will turn but won't start because the timing is so off. I read the manual on how to adjust but it requires the engine to be running and well....hence my problem. Any suggestions?

Loosen the bolts holding the dizzy, turn it back then try starting the engine? Try turning it in different positions.