Thomas,, I also snapped a bolt on my early engine in my chevy II, on second try, I mounted the manifolds together first, not tight but pretty snug, then mounted the manifolds, i had to pry (spread) apart a little at the ends over the guide pins,, after is was on, then I tightened the heat transfer for good, then torgued the manifold on,, worked great no leaks,,if you're like me and have a million gaskets laying around make sure you are using the metal(thick)type exhuast gasket, not the paper ones that might come with aftermarket manifolds,