Keep blowing exhaust manifold gaskets- why?

[66/72RAB]

Hey guys , looking for some suggestions?? - I am blowing exhaust manifold gaskets at a somewhat regular rate.  Right side is the culprit. Not sure it matters but car is a 72 , I am running a basically stock 340 with stock manifolds and a 2 1/2" TTI exhaust system. I am guessing that the manifold might be warped. Any other ideas or tips? - Thanks

[72cudamaan]

I'm sure your guess is spot on. Have it milled and you'll probably
be good to go.

[burdar]

Your car didn't originally come with exhaust manifold gaskets.  Both surfaces were machined so no gasket was needed.  Once you get the warping issue resolved, you shouldn't need a gasket.

[1of1]

Your car didn't originally come with exhaust manifold gaskets.  Both surfaces were machined so no gasket was needed.  Once you get the warping issue resolved, you shouldn't need a gasket.

Wow , never seen a motor from detroit that did not have manifold gaskets , were there other years or engines that did not have them? Like my 383/335 comando?

[Chryco Psycho]

I agree , the reason you are blowing them out is because they were never supposed to be there , I use a thin layer of Ultracopper RTV & bolt them up

[Jim]

Factory did not use gaskets, but those were virgin machined surfaces. Milling might be in order, especially if the surfaces have been exposed to leakage for an extended period. They will corrode and erode.

SB heads are bad about leaking between the center ports. Not much clamping force there. I've had to have the sealing surface on cylinder heads milled quite a bit to get it flat again.

The thin layer of copper RTV will work to take out slight surface imperfections.

[rusty dodge]

Make sure the flange is still thick. In this pic, the right port is thin or worn away. Pic is after I belt sanded all the ports flat, and thats all the thickness i could get from it. Used a pedistal type belt sander with a long wide belt.

[66/72RAB]

 Appreciate the input guys. Here is what i did. Pulled the manifold off and checked it , it lined up nicely with a straight edge so I do not think this was the problem.  I am going with the idea that it is just not supposed to have a gasket. Put it back together with a thin bead of Ultra Copper as suggested. First trip out, so far so good. Thanks to all.

[Chryco Psycho]

A friend had the same issue , the gasket would last about 4-500 miles & fail , he left them out & was fine , the factory never used gaskets , I am sure you will be fine now .

[mrbill426]

Is this true for the big blocks too, no gaskets from the factory?

[Chryco Psycho]

yes . the only engine I can think of that used a gasket was the 340 with the heat sheild to protect the wires on the drivers side , it was a stamped steel gasket

[mrbill426]

Okay, thank you