gasket or no gasket

[tjc]

I am putting factory exhaust manifolds on my newly rebuilt 454, and my engine builder said I should bolt direct to heads no gasket. What are your thoughts on this?

[geezer#99]

If they are new you don't need a gasket. If used then use a gasket. Used might not be perfectly flat.

[kwmech]

Metal to metal. I always butter the face of the manifold and the bolts with antiseize.

[68gmsee]

Non of my V8's with factory manifolds ever had a gasket. A good machine shop will face them flat if they are weathered or pitted at a nominal charge. Worth doing it and not having to mess with burned gaskets.

[Ironangel]

As noted above, as long as the head mating surfaces and the cast iron manifold surfaces are flat and scratch/nick free, no gasket is necessary. I have used the copper based high temp anti-seize to good result. I am currently using a trick I picked up from this forum for header bolts, wrap the bolts with Teflon pipe tape and they will stay tight and not back out until you put a wrench on them. I have also used a copper based high temp rtv silicon in place of a gasket where questionable wear and corrosion were visible to good effect. The factory did not use exhaust manifold gaskets, but they isolated the cast iron manifolds with spring loaded donut gasket connections that allowed some flex reliving the stress that often compromises the head to manifold connections. I have taken my rams horn manifolds to the machine shop and had them resurfaced to true the surfaces on castings that had leaks that went unchecked allowing the mating surfaces to corrode.