I was getting ready to replace an exhaust manifold gasket on my 67 425, yet again... and someone suggested that the reason I am constantly have leaks is because they originally did not take a gasket, just manifold straight to head... is this true? It had manifold gaskets when I got it, but this will be the third time I've had a leak. Any suggestions?

 

The factory did not use a gasket, just metal-to-metal. If the manifold and cylinder head mating surfaces are flat (check with a metal straight edge), no gasket is required. If they are not flat, no gasket will seal anyway, so make them flat and bolt it up like the factory.

 

I was getting ready to replace another manifold gasket on my 67 425 (yet again)... and someone suggested that the reason I am constantly have leaks is because they originally did not take a gasket, just manifold straight to head... is this true? It had manifold when I got it, but this will be the third time I've had a leak. Any suggestions?

 

Manifolds are probably warped, remove and check to see if they may be resurfaced. If the warping is excessive then too much metal will have to be removed and warrant locating a replacement for the manifold. Advisable to not use gaskets. If enough metal is removed from the left one the dip stick holder will not fit between block and manifold. Manifold warp often results from over heated blocks.

 

as the manifold ages and corrodes i think it will need gaskets to seal properly.i remember having gasket problems until i started using new bolts when changing manifold or gaskets and using a felpro gasket. do you have bolts that loosen up and cause the gasket to blow?i feel the new bolts would cure that. hope that helps.

 

The manifold can be milled true and then you may not need gaskets but the head surface may also need a cleanup mill.

 

I can't get the left side manifold to seal with or without a gasket... tried new bolts & lock washers... even tried copper gaskets. From underneath, I can see the gap at the very rear of the manifold, so probably too much to have milled.

Are these a good option for me?? If so, what's the best way to eliminate the damper on a brand new manifold (I had the old one cut out with a torch... I would hate to do that to a new one).
http://thorntonmusclecars.com/produc...aust-manifolds