In the past 2 weeks, I've put 2 exhaust manifold-to-cyl. head gaskets on my 71 440 R/T. They ALL leak from the bottom of cyl. 3/5. After looking at the Fel-Pro gaskets, it looks like the bottom of the center exhaust ports just don't get drawn down tight enough. I've checked for any other causes, but ... I cleaned the ever lovin' crap outta both surfaces thinking there was gasket residue...but nope...still leaks.

So...I once again need to fix the leak.

Anyone have any tricks, or any suggestions on WHAT gaskets to use to fix this problem. I realize the maifolds may have a slight warp, which is causing the problem...but I REALLY don't care do deal with having the manifold planed down, unless I have NO other options.

Thanks in advance...

Try some of NAPAs Nitro Seal header gaskets. Thay are made out of graphite. I have had great results with these on small or big blocks with or without headers. They are slightly expensive tho....Around 30.00 a set

Mike .....two options as I see it ..... but you MUST get those manifolds milled if they are warped.

Either go iron-to-iron like the factory does. OR go with a set of copper gaskets. Either way ... the heat from the mans will be exchanged into the cyl head. A regular gasket will not allow that "exchange" and will-warp .. big time.

I had the same issue with my 440, I got a gasket from a place on west coast, cannot remember the name, but it was a thick silver gasket and it worked perfect, This will solve your problem,if no one else here brings this place up I will check later as to what place it was and post it here.

There is another trick get ultra copper (choose colour) high heat silicone and apply liberally to both sides of the gasket. Tighten lightly and wait 15 minutes then snug medium snug and wait 2 hours or more (overnight) now tighten good start up and let it run till hot re tighten. after a few days tighten cold. then check tightness periodically.
This is the cats $%% on poor fitting flanges

Mike put the manifold, gasket side, on a flat surface and shine a light from the opposite side of where you are and look at the surface on the table , IF you see light it's warped and needs to be machined flat .

This will solve your problem http://www.remflex.com/

The copper gaskets have worked for me.

the rimflex and the NAPA Nitro Seals are the same...

My brother went with copper rtv instead of gaskets on his 455 buick exhaust manifolds. No leaks.

Thanks!!

REMFLEX.COM,by far the best!!!!!