Total timing and hot exhaust manifolds

[FredJ70R/T]

Anyone know why one exhaust manifold would be hotter than the other. My driver side exhaust manifold is about 100 degrees hotter than my passenger side. I am working on setting my total timing on my 440 4brl. Right now I have it advanced about 15 degrees. Starts right up, but backfires when I put in drive. That’s at 1050 RPM.

 

[RemCharger]

Perhaps a vacuum leak is leaning out one of those cylinders

 

[F4R/T]

What are you engine specs? Big cam idle & cranked up to get into the primaries? Your Vin doesn’t end in 626 by chance?

Check vacuum and timing

 

[RemCharger]

Exactly. How did the 1050Rpm come about.