Exhaust pipe to header flange question

[66furys]

I just got a new system that I am mostly happy with, but have a question. The pipe thru the new flange for the header joint, has been swaged over the flange in a nice clean arc. But, this sits proud of the flat flange, and I am concerned about the seal. Vendor says that the cast header has a fillet, for lack of better word, for this to recess into. If not, am reviewing how to weld the pipe to flange during install process, after align to the manifold, and grind the flared pipe down. Also, I do not want to just crank down on this joint with a gap, that might crack the header ear. thoughts appreciated.

 

[CBODY67]

Were there not stamped metal gaskets that went between those pipes and exh manifold flange ends, to seal them? Does "header" really mean "cast iron factory manifold" rather than "steel tubing aftermarket headers"? Just curious.

Seems like the retainer torque at that point is something like 35lbs/ft? Is the floating flange a bit convex to the mounting surface, for increased "spring action" as it is tightened down?

Just some thoughts,
CBODY67

 

[66furys]

Yes, I am retaining the cast iron factory manifold. I am just wondering whether there is a filet inside the flange that this raised section of flared pipe will fit in. If the joint surface is flat, I am going to see a problem. It seems that some mfrs simply weld the pipe into a flat flange that is between 1/4 and 3/8 thick. In this case, they just flared the pipe on the upper side of that flange....and this will create a large gap, if the header flange is not relieved to take it. The current exhaust system, not OEM, has a simple gasket and it totally closed up tight. I obviously have not taken this apart yet.

 

[66furys]

I would still like to hear from someone that has the iron headers off a 383, to know whether the outlet flange has a relief cut or fillet inside....please go kick one over and lemme know what you think. thanks

 

[Dads300]

Big block manifolds of the 60’s-early 70’s have flat flanges that use flat gaskets. In the mid 70s I believe they went to ball flanges.
Travis..