My new engine is installed but I am having some trouble getting it to run right. For the first step I rechecked the timing and with the vac advance still hooked up, I estimate the timing was ~35 degrees advanced. I originally set the timing at 6 degrees with the vac advance disconnected and was surprised how advanced it was under vacuum. Is going from 6 to ~35 after reconnecting vac advance normal and should the vac advance be disconnected when doing the timing? I believe my distributor is the stock one for a '57 312.

The running problem I am trying to find is the car dying when I try to accelerate as well as backfiring before dieing. If the timing change is normal, then I will need to head down some different paths. My initial thought was carburetion, but I completely disassembled my Holley (stock for a '57 Tbird), blew out all passages, and reassembled so I am looking at timing now.