When bolting my L67 to the trans the bottom most bellhousing bolt, near the rear exhaust manifold and passenger side axle shaft (threads are in trans, not engine), kept spinning once fully seated. I removed the bolt and discovered threads from the trans portion were on the bolt, broken loose from inside. I got a 12mm x 1.75 thread tap to see if I could chase the threads but the bolt still spins when fully seated.

I have a couple of ideas on how to fix the situation and wanted to get others input.

1. Drill out the hole and retap to the next larger bolt/thread (not sure what size that would be).

2. Use a heli-coil kit (never used one before

3. Some type of locking washer/nut to allow the stock bolt to tighten up fully.

The threads that came out are the inner most ones, they were on the bottom of the bolt threads when I removed it. Any help would be appreciated!

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Project L67 Fiero

Either of those approaches will work, that is, a Helicoil insert or drill and tap for a larger bolt.

Just make sure you use a bolt that will access all the threads for maximum support.

Helicoils work great, I've had to use them thousands of times. 2 tips on using them, install with red non-removable lock-tite and run a tap into it after the lock-tite has set.