416 issues - losing patience

38 degrees timing sounds pretty stout with pump gas. I run 34 with 9.8 to 1 compression and aluminum heads on 91 octane california gas.

Most aftermarket electric fan setups are not adequate.

If you are running a aluminum 70 up water pump, you will need the Jaguar short fan clutch (Hayden #2765). You might be limited on the diameter of the fan depending on where your upper radiator hose is mounted in relation to the center of the water pump. Looking at your picture, I think at least a 17" fan would work. Maybe someone else here has ran an 18" with that Champion model?

I built a fan shroud for mine. But it wasn't really bad without the shroud. I would just run the mechanical fan first. Check out what is going on. Then get/build a fan shroud.

Building a fan shroud step by step: http://www.forabodiesonly.com/mopar/showthread.php?t=198911&highlight=cooling