Quote Originally Posted by IC2 View Post
Sanderson and I had a "discussion" about this very subject. They are full of c@#p with the RTV. Exhaust flow can reach 1200*F on occasion and that RTV is not acceptable. As far as flat - they build up the flange with MIG weld then grind it - and flat, mine sure weren't!!! I looked at the Fel-Pro gaskets, but the holes were too small for the GT40P heads so ended up with these from Earls - not cheap, but a quality part: http://www.summitracing.com/parts/EAR-29D03AERL/
That does not mean the RTV gets to 1200 F. If it did your aluminum heads would also melt. The weld beads on mine were fly cut and very flat. If installed per manuf instructions they will work fine.

Kitz