Just bought a smoke machine.

ProjectBazza said
My God, I hope it's that simple! I had a '92 F150 with a 351, and when I replaced the engine years ago I found the same thing: No factory exhaust manifold gaskets.

I had forgotten all about that....

Thanks!

I never use gaskets on stock manifolds, unless they are badly pitted. Never had one leak without the gasket, but plenty that did with one.