89 xj exhaust manifold bolt busted off in the cylinder head
 

Hoping someone can give me an idea of how far the studs for the exhaust manifold go into the head On a renix 89. It was snapped off when I got it from the PO and thought since I’m doing freeze plugs right now it would be a good time to extract the broken stud. Well the D*#! Thing would not budge after soaking with PB Blaster for days and applying heat. The extractor has now reamed out to big to keep up with that idea.
If anyone knows how far that stud goes into the head I plan on drilling and tapping it. Can I use a regular bolt to replace the broken stud????
Any help will be greatly appreciated.

Those 3/8-16 studs go into the head exactly a half inch. Sure you can use a 3/8-16 bolt to replace the stud.

Thank you for responding Randy.