Just a quick question. There is a hole at the bottom of valve cover hole that goes right into the intake side. The hole is about a 16th of an inch. Since the bolt to the valve cover threads inside and proably seals it, what kind of material could be used to fill the hole at the bottom. Maybe something made by Permatex that is gas-resistent. Any help would be greatly appreciated.

JB-Weld should be fine on the intake side of the head.

I wouldn't try to fill the bottom of the hole. What happens if the VC bolt pushes it out? I'd just seal the VC bolt threads

If it's threaded all the way thru then the JB-Weld "probably" won't fall out.

As mentioned you could just seal the bolt instead. A little plumbers paste on the threads before it goes in should do the trick. Some cylinder heads have bolt holes that go into the intake ports so if it was a big deal they wouldn't do it to begin with.