Blugene, the hole should not be hard to figure out...take one of the other bolts and use a thread gauge and just measure it,probably a 7/16 course.
If a one size up bolt will fit through the hole I would just oversize the thread and call it a day. Heli-coils are great for aluminum and mag and stuff, but I like to use parent metal as much as possible on steel and cast iron. Just one less thing to go wrong. Threaded inserts are the best way to go a lot of the times as long as the prep hole doesn't put you into a thin material condition anywhere.
That's what it is, but only for the last about three threads. I will have to go bigger, I have the bolts that I am thinking I want to use. I won't get to get back on this untill mid week. Been sick the past couple of days. Kinda over did it the one night when the first mount and I fought for about six hours . I finaly kicked its azz, but the other side is trying me. I have about two hours on the second side so far. By no means am I bragging, cause that is actually embarrising. There was a time when I would have something like this knocked out in an hour for both sides, now i'm bragging, . I need more nyquill, later.
Are you saying only the first 3 threads are messed up? If so have you considered using a stud? (goes along great with the thread title)
Ok, I now have a tap and the correct drill, bolts, lock washers for the repair. I feel better and will be attenpting to get er done this weekend. I spent $39.00 for the stuff so I hope it works. I'm tired of seeing the darn hoist hovering over the engine bay! And i'm tired of crawling around underneath it too, sheese.
jegs sells a engine block crack filler.you pack the hole real tight whait a couple of days for it to dry ,then drill it and tap it .it worked wonders on a 289 with the same problem. we were imprest!
D_O_N_E ! It's only 106 in the shop today, so I was able to tap both left mount holes today and i'm still goin. I'll be gettin back to the gas tank project in a few but I wanted to show some pics I took so... The engine stand is one of my best investments, I think. $179.00 assembled is what I paid, and it folds up.
