Anyone know offhand what the size and thread are of the distributer cap bolts? I need to helicoil my base.

 

No. But why don't you just use a larger screw? The base is aluminum so you should be able to force a re-thread.

 

Id rather helicoil so I dont ahve to mod future replacement caps to fit teh base.

 

Knowing GM it's probably an off-the-wall size like 4.5mm 28pitch. Just a guess. I don't have a tap and die set.

 

It appears to be a #6 wall socket thread, but I couldn't find a screw laying around to test.
Stripped mine, but there's a relatively easy fix.
Take a pair of fairly good size vice grips, and crush the aluminum plate at the hole.
Thread the stock screw back in. DON'T over tighten it ! It won't take much to strip it again if you do. ( don't ask ) Next time ( yeah, right ) I strip mine, I'm gonna look for some of that aluminum solder, solder up the hole, and start over.

 

Theyre finer then a #6-32, but larger then a #4-40. Probably some odd metric size. Im tempted to buy a slew of small bolts from a specialty house to see if I can match it to something

 

I guess if I had to take a guess, Id say its either #6-40 or 3mmx.5.