Could someone tell me in detail how to replace the studs from the manifold to the exhaust collector? I tried to replace the collector gasket and in the process stripped the stud (lug?). (In my defense it was rusty) Im pretty handy but have limited tools.

Thanks to all for your wisdom.

oh..its an 84 240 with 165k.

A method I favor applies heat to the stud using Mapp gas, warming it as quickly as possible without dragging out oxyacetylene. When the end is red (the aluminum head is a huge heat sink) shut off the torch, and quickly feed the joint some wax; I've used beeswax, candle wax, even a chapstick. Then apply vise grip pliers coaxing it both directions until it (always) loosens, to turn it right out. You still have to be somewhat aware as to how much force can be applied to materials, hot or cold.

If not successful, don't try an extractor. But you will be successful.
--
Art Benstein near Baltimore

Art -- If he's asking about the manifold-to-downpipe joint, does your method still work??

Oops, thank you! I need to read more carefully! And my sincere apologies to 240snowmobile for imagining using a propane torch to heat up a head.

I've coaxed the ugliest masses of rust that used to be 8.8 bolts in a threaded cat flange, using that method a few weeks ago. So I believe being steel to steel is not a factor. Amazing trick, I learned it reading this forum. I removed the studs on a turbo that way too, but they had not been broken first, so I baked a pair of nuts too. Birthday candle.
--
Art Benstein near Baltimore

Roasted chestnuts I hope!

I think might have to completely remove the exhaust manifold from the car to work on. Then heat the area around the stud - but not the stud itself - with a small propane torch. Grab the side of the stud with visegrips as tight as you can and cross your fingers it comes loose. Try it on the car first if you have the room to work; who knows, you might get lucky.

Otherwise you will have to drill out the center of the stud and pick out the remaining pieces. I've never had a lot of success with EZouts (stud extractors). They always seem to break inside and then you have an even bigger problem.

You might want to clean up the threads on the mani with a tap before you put new studs in. Have fun.