I fired up my motor for the first time last night after the rebuild. New pistons, rings, rods, bearings, main caps, etc..

I borrowed a carb (950hp) for the break in before the FAST kit.

I know motors tend to run a little hot on initial run because of everything being tight, and the collector ends of the headers (these are shorty) were red and flames were shooting out while it was running at about 1600-1700 rpms.

I am assuming this is because the carb is dead fat and the excess fuel is burning off? The plugs were very black too.

I have never run a motor with shorties, much less open headers, so I don't know if the "flames" part is normal? Water temperature wise, everything was normal.