I built a very similar combo in 1999. I had that exact fan. It was not up to the task,even; with a shroud,and a hi-flo Milodon pump,and a Hi-flo stat.,and a 26inch OEM A/C rad. It wouldn't have any of it.An OEM, 7blade A/C fan with a Ford thermo-clutch has been doing it for me since then.
During cam break-in be very careful. Keep a running garden-hose handy, with a helper manning it, and the IR gun.Get the rpm up ASAP, check for leaks;especially fuel, give the dizzy a twist until the rpm maxs out. Forget about the exact timing until later.
Then relax a bit, for twenty minutes.
The #1 thing is to not have fuel leaks. If you have to shut it down, do it!
All the best to you and everyone else, during the break-in, and afterwards, keep it between the ditches;Yahoo! I love my 367 cuber.