What's the size of the bolt holes on the intake manifold? I'm having some alignment issues. Most of the bolt will go in, but a few are just slightly off, so I want to drill the hole out to the next larger size.

I think the actual intake manifold bolts are 3/8, but want to know what the actual size of the bolt holes are. Would they also be 3/8?

 

A quick check with a digital caliper shows them to be in the range of 0.435-0.445". That would be about 7/16". The next size up would be 15/32" (0.46875"). Why are you having alignment problems? Were your heads cut?

 

Thanks for the help, Fred. As always, you're a big help.

The heads have been cut several times. At first alignment was way off, so I cut down the intake manifold flange also. It's much better now. Most of the bolts will go in and thread properly, but a few are just slightly off.