Well after my th350 swap, it went a little to easy. I Now have 2 trans crossmember bolts stripped, 1 on each side. I was going to try to re-tap them, see if that works, but I think im just pissing in the wind, so to speak.

My buddy said he had to cut a hole in his subframe to weld new nuts in there. Is that the best way to do it?

I have hochkis SFC, but am hesident in doing this because our cars are kinda weak, espcially with a 383 stroker putting out 525FTLBS of torque

Is that the right way to do it?

I know this would be alot of extra work, but if I removed the carpet, and drilled a hole in the floor pan to put a nut in there, that would kinda be better, but alot more work. I dont mind doing more work, to do it right.

 

The factory fix is to drill it out and re tap it to a bigger size. I had to do that with mine. Kind of a pain to get the tap to go in perfectly straight while laying on my back. I forget the size.

 

Going through the interior is actually pretty easy... just peel back the carpet, mark the bolt hole from below with a punch, cut a nice neat round hole (about 1½" should do) with a hole saw, do the nut thing, plug the hole with a rubber or plastic plug.

 

I took a mototool and cut about a 1"x2" square hole in the sub frame. Big enough to fit a 3/4" wrench in there to hold a nut. Didn't have to weld the nut in. It works great.

 

I used a magnet and dropped a bolt into the subframe from one of the existing window holes in it. Carefully dropped the 1" allen bolt through, and used a nut to hold the crossmember on. Once I started tightening I didn't even need to hold the bolt head still... Worked really well.
Drilling and re-tapping rarely works, that metal is soft like cheese. Try a search, this is a REALLY common problem.

 

When I built my crossmember I used all three holes on each subframe.
Drill them with a 25/64ths drill bit and then tap them to 7/16-20. Works great and only takes a few minutes.

 

Had the same issue. The tranny shop that got too hasty and stripped it heli-coiled it. I noticed it isnt very snug and will probably need re-done when I have to drop it again. But for the time being Im going to wait on it. Ill probably cut an access hole.

 

I used an impact punch to knock the old nuts out and fabbed up a metal plate with the 2 nuts on it. you slip the plate up into the sub-frame (use the stock holes, you'll see em') and just thread the new bolts in. worked nice and i didn't have to cut/drill/tap anything.

Ty