Like 3B says, replace or repair are both options, your situation will help determine which is the best option.

If helicoils will repair the threads which I think were originally 3/8-16 I'd probably try that first, less effort.
But if the flywheel housing is trashed I would have no problems replacing it, they are easy to find.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-