Originally Posted by Erockstrobez08
Which stud broke? It's hard to tell from the pics what you have left to work with. And I can't remember much about my 3.5's throttle body. But, ideally, you would like to be able to remove the broken stud and replace it. Can it be unscrewed? Is it pressed in? Would you have to drill it out and then tap the hole to put another bolt or all-thread in it? (The all-thread would have to be glued into the new threads to fashion a stud.)
Anyway, replacing the broken piece would be my first approach. If the drilling/tapping/etc requires removing the plenum, then I would have to seriously consider replacing it.
Likewise, if repairing it does not look possible, then a new upper intake - aka, intake plenum - is in order.
Looking around on the web, I had little luck finding one (which was a surprise to me). The p/n I came up with is 12611485 . I see it at about $1000 at the online GM parts houses, www.gmpartsdirect.com
So you're going to need to find one at a junk yard, if you have to replace it.
I encourage you to poke around some more on the web to confirm what I found. Start at the GM parts vendors above to confirm the p/n. Then search for that at places like oreillyauto.com and napaonline.com for aftermarket parts. (I couldn't find any.)
Write down your VIN and have it handy. There are two 3.5 options. I think they both use the same plenum, but have that ready if asked. I think it's the 8th character that identifies the motor.
Lastly, tell your buddy to learn how to use a torque wrench, to learn the difference between inch-pounds and foot-pounds.
In some case, for small fasteners, I will only go with half or 3/4 of the spec torque. I'd rather have it come loose than break it off over-tightening it.
You should be able to get a good plenum at a salvage yard. My first guess was $35. But seeing how scarce and expensive these are in the aftermarket, I'm now thinking you might find yourself paying 100 dollars or more. You'll need new gaskets to go with, two plenum gaskets and maybe one for the throttle body.
Good luck with it. Post back and share what you end up doing.