Helicoil make a insert you can drill the hole out and put the insert in and stay with the same sise bolt or you can change it over to a regular sae bolt.
Depending on what helicoil kit you use metric or sae.
The hardest part is getting the having enough room to drill it out.
On the tap you can use a wrench instead of the tap handel in a tight space.
Good luck
MT-2500