One of the bolt holes in my TPI Plenum is stripped (The front most hole by the TB at the driver side). You can tighten it as far as you can with a bit driver, then put a small amount of torque on it with the tq wrench after that but then it just spins. I'm not worried about a vac leak at this point since I was able to torque all other runner and Plenum bolts to 25 ft/lbs no problem.

The next time I have the Plenum off, I was wondering what the best approach at a repair would be. Should I have the hole drilled and tapped for a slightly larger bolt or have a threaded insert put in? I'd like to avoid getting a new Plenum since I spent a fair amount of time porting and painting this one.

 

A coiled thread insert is probably the best option since it is a relatively thin area in the plenum casting. the torque for those bolts should be about 18 ft/lb so an insert would be adequate. You will need an insert kit with the proper tap and coil insertion tool.

Heli-Coil is a common brand, but Chrislynn seems to offer a wider variety of materials, lengths, and pitches.