Are all the bolt holes used when mounting pontiac 400 exhaust manifolds??
While replacing a warped 1971 pontiac 400 Lemans sport exhaust manifold, I noticed that it had only four bolt holes: two on the inside of the outer ports and two around the inner two ports. The used replacement manifold, which fits fine, has 2 extra holes on the outside of outer ports. The block has holes to match, but the picture in the factory manual does not show the bolts being used. To further add confusion, the maual states that the gasket can be hung on the outer bolts to ease installation, implying that they are used. Does anyone now the differnce in the manifold, and weather all bolts holed should be used?? I don't want to over constrain the manifold and break it!! Thanks
bluesjon@aol.com