52 Mercury Flathead runs rough.

[ling102]

I have a 52 Mercury Flathead V8 in my 48 Ford Coupe.
The car in new to me.
It has an Offenhouser intake.
It has a Holley four barrell carburator.
It has Reds headers.
The motor runs rough.
I have 100lbs compression.
No overheating.
Good oil pressure.
No vacuum leaks.
The plugs look ok.
However, I have one backfire
when I start the car.
Could this be timing?
Any help would be greatly appreciated.
Thanks guys.