Need Quick Bolt Help!
 

Finally was able to get those two stubborn nuts off of where the midpipe attaches to the downpipe today, and put on my new dp. But when I put the two new nuts on the old studs (couldn't get those out) they threaded halfway in and then just stopped threaded; they just sat there and spun. I thought maybe it was on tight enough for now, but when I started it up - exhaust leak from hell! It was so loud! So my question is, how do I get those nuts tight? Would it be possible to but a nut 1/16" smaller and just crank on it as hard as I can to possibly re-thread the stud to the new size. Please help! I need to get this thing running!

To your putting a smaller nut idea: NO. You could try to rethread it with a die, but chances are, those studs are screwed. Take it to a muffler shop and have them remove the old studs (they will probably have to use a torch or plasma cutter), then just use nuts and bolts.

Before going to the muffler shop soak the studs and try to remove them with vicegrips , then replace the studs or drill out the threads and use SS nuts and bolts. If vicegrips will not work drill the studs out.

Drilling the studs out will take forever, and burn up all of your bits. Trust me, I've been there. Using a pneumatic drill with 4 sharp MAC bits I could only get about an inch into one of the studs. Then I broke out the oxyacetylene torch, and it took 20 seconds to get out. Don't waste your time or tools.

Thanks guys. I agree with P'cola FD on the no drilling idea. I tried that one the first go-around with the dp when I couldn't get the nuts off. Went through two drill bits and maybe made it 1/16"! I'm going to see if I can find a torch from someone to take those studs out, otherwise I might try to take the entire mp section off and take it in somewhere. If I can't get that off, is it safe for me to drive to the shop? If the leak is big enough, isn't it essentially the same as running an open exhaust?