If you work on these things much this Kaystar 972 set is well worth the investment.
http://www.amazon.com/s?ie=UTF8&keyw...40%20pc&page=1

 

In stead of replacing the factory stud is it possible to just drill all the way through and install a traditional bolt and nut? If so this could be done from underneath with out removing the manifold.

 

Gale is right.
Well,
If you have drilled out the studs.
You need to now go and get the TAP and tap out the holes.

And I think you ordered new studs.
I got mine from
Rimmer Brothers - Triumph Car Parts, MG Rover Car Parts, and Land Rover Car Parts and Spares

Once the holes are tapped -
put in the stud into the hole

Then try to put a nut on it.
Try to torque it to the specified torque.
If you can't then you are done.

You will need to eBay a manifold.
And, most of those are junk..

I just hate touching this stuff as it all breaks. If I can let exhaust alone - I do not touch it. Always breaks.

In my case I broke a stud.
Got it out with a stud remover socket.
tapped the hole

Put in a new stud.
It held and is holding three years later on a DI.

 

This is running off memory, but some of the tapped holes are through holes and some of them are blind holes (don't go all the way through), only way to tell is feel the opposite side of the flange for a hole. It is possible to drill from underneath but it is a lot of work. I've found it much easier to pull the manifold. If you've got the "Y" pipe unbolted it's only 8 more bolts and the manifold is off.

 

that would be easy, but how risky for the bolts to break off in the head? They look really rusted.

 

If its one of the exposed holes it would seem easy to drill all the way through and drop a bolt through. If I take the manifold off will I need new gaskets between head and manifold or can the old ones be reused?

 

Gale is correct.
Take off the manifold.

Just get a 12mm 12 point.
Loosen the bolts. Just a little.
Then tighten.
Then loosen.
Tighten, loosen.
Always go a bit loose when it gets tight, but then go back the other way.

Never put too much torque on the bolt in one direction or it will snap off.
You need to go back and forth to avoid snapping them.

I suppose WD40 or such will help - if it can get into the threads.
I am doubtful how much that works deep into an aluminum head.


When I changed heads - I only had ONE bolt snap out of two manifolds.

Gale's memory is correct. One hole is not straight thru.

Rave manual says to REPLACE all these bolts to new when removing.
I removed mine and replaced them.
I did find some NEW bolts on eBay for about a buck a piece.

 

You should use new gaskets. It's not going to be easy drilling overhead either way (drilling and retapping for a stud or drilling out to put a bolt and nut in there) I'm not a big fan of the bolt idea, but have seen it done on various vehicles over the years. I've also seen the exhaust manifolds on those same vehicles with the "ear" of the casting being broken off by overtightening the bolt/nut combination. (not to mention that a one man job becomes a 2 man job) BTW WD40 is worthless as a rust penetrating oil, it wasn't designed for that purpose, Kroil or PB blaster is much more efficient and will over time penetrate through rusted threads. WD does a real good job when it comes to melting plastic though.

 

You really can't accurately drill unless the manifold is off.
You need to get a center punch in there to get the hole started.
If you are doing it with an extension on your drill, you'll risk running a hole into
the cast iron between where the bolt ends and the cast iron starts.

When drilling blindly, that is where the drill always ends up.
Then the manifold is ruined.

 

There is plenty of stud sticking out if I drop both down pipes I may be able to get it out with a stud remover socket, this way manifolds would not have to be removed.