stripped out bolt holes

[smallblock]

I just dropped a rebuilt 360 out of a 1976 Ram charger into my 74 Challenger. When installing the headers the rear hole on the passenger side stripped out. I think by the way it felt it was already stripped out or close to it. I know these usually has the studs already in them and kind of thought they were fine thread but 5\16 18 bolts fit the other three outer holes and tightened up fine. I was wondering if this has happened to anyone else and what they did. Im thinking of tapping it out to the next standerd size that I think is 3\8 16. My concern is there's not much meat in that area of the head with the freeze plug being right there and I don't want to ruin the fresh head. Any help (I always get it from all the great folks here) will be great. Thanks.

[jimynick]

Beg, buy, borrow or steal a heli-coil kit with the proper sized drill and installation tool. That's if the hole is a dry hole. If it's wet I'd go oversize as you mention, but there's way smarter guys here who may have a better idea. Just my 

[Rich G]

I agree, heli-coil and some lock-tite you should be fine.

[smallblock]

Its a wet hole. Its actually leaking anti freeze so thats why i was thinking of going oversized but wondered if anyone had done it so I knew there was enough iron there to go bigger without problems.

[HP2]

Bigger thread size may also mean a bigger hex head which will lead to even less wrench clearance and possible flange modifications to allow it to fit.

I would heli-coil with a generous amount of red Loctite. Then Teflon tape the header bolt.

[burdar]

Drill it out to the next size and re-tap.  That will work just fine.  I had to do that myself.  I machined down one end of a 3/8" stud and re-tapped to 5/16.  The 3/8 end goes in the head and the 5/16 end is sticking out so you can use a stock fastener.

[crash340]

I drilled and tapped to next size up, didnt have to turn it down like Burdar but was prepared to in case I needed to Im running TTI headers as well, no issues, no leakes 

[vinb]

Did one on mine end bolt,  Heli-coil kit and orange high temp silicone ,  no leaks.

Works for me and if it fails then use can always go up one side may be to 11/32"