A TIMESERT might be a great solution to this problem. Much better than a helicoil.
The actual TIMESERT itself is made from unobtanium and very strong and should never strip out.
94 RMSB 170K Sat 5 years, ran for 1 of those then remained untouched for 4. Sat because it was slapped by a deer and the owners didnt want to fix it for whatever reason.
Mods, all the free good ones.
Future? Probably pull engine, reseal it, and run it a lot more. Looking to get 250k out of it. PRAYING for 300k.