As usual, I got myself into another unplanned snafu! Replaced my thermostat and ended up stripping the threads in one of the water neck outlet pilot holes in the manifold (Edelbrock Performer). Thinking about helicoiling, but the pilot holes are not deep enough for the helicoil (the shortest length helicoil for that bolt size is about 1/2 inch deep). I would need to deepen the original pilot hole by about 1/4 of an inch to get the helicoil to fit properly. Not sure if this is a good idea or not. Anyone done this before or any thoughts? I guess if I screw it up I can just get another manifold!
Thanks as usual for the help!

I'd drill the hole a bit deeper then install the insert. I have cut a coil or two off the inserts with side cutters before installing a few times when the hole could not be deepened.

Bluebird, thanks for the input. Yeah, I am thinking I'll give the insert a try. If that doesn't work then I guess I'll need to replace the manifold. I would think that I would have enough room depth wise to drill the hole deep enough to accommodate the insert. Good times........

I put a helicoil in my Edelbrock with no problems.

Thanks Glider. Yeah, I will give the Helicoil a try. Still debating on deepening the hole or just cutting some coils off. The holes for fastening the water neck outlet/T-stat are very shallow, especially the rear hole. That one looks to only have room for about 3-4 threads...

Found bad threads on one side of mine nite before go'n to the track, and didn't have correct size insert.
Ended up clean'n out bad threads, the chased to next size larger bolt. Been fine for years.

The same thought occurred to me. I did that for a stripped out starter motor bolt (into the aluminum tranny bellhousing) on my 1st car. Never had a problem.

Thanks for the suggestion. I ended up just finishing installing the Helicoil inserts with no problem. I was wrong about the depth of the holes though. The reason why one appeared only half as deep as the other is that there was a bunch crap compressed into the bottom of the hole. The original depth of each hole was deep enough to accommodate a 1/2 inch long HeliCoil insert, so didn't have to cut any coils to make it shorter. Thanks again for the guidance!

On another note, the 69 Service Manual states that the intake manifold water outlet fitting bolts should be torqued to 30 FT-PD
Seems pretty excessive to me. I found a lengthy discussion on the forum: https://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=252341&Searchpage=2&Main=28866&Words=%22thermostat%22&Search=true#Post252341

But no mention of the 30 FT-PD.

I'd say it's a bit much as well, but I'm sure that is spec, they didn't want it to leak. An original cast iron manifold may take it but an aluminium manifold may strip. If I'd been thinking, and not in a big rush, I would have heli-coiled my manifold when I took it out of the box.
Same thing has me worried about my aluminium heads, none of the threaded holes are heli-coiled.
And just last week I had to heli-coil threads in the cast aluminium 68 power steering/alternator bracket. Aluminium is great stuff but work hardens rapidly and is prone to galvanic corrosion. After suffering from belt squeak for years I changed pulleys and belts many many times, the bolt hole in the bracket finally work hardened and stripped out. It was a pain but I managed to drill out and heli-coil it in place.

Good point on heli-coiling the aluminum manifold right out of the box. And funny that you mention the PS steering/alt bracket. Like you, I have had to disconnect and re-connect the PS pump and alt many times and it recently struck me that I should just hell-coil the bracket. Doing that doesn't seem too bad compared to heli-coiling the fastening holes to mount the tranny pan. I stripped a couple of those holes out and decided to just do all of the fastening holes. What a major PITA. Car jacked up, laying on my back, not much room and trying to ensure I was drilling out the holes straight. ...And I had no experience doing any kind of tap and die work whatsoever.....Knowing that I had only one shot to get it right was unnerving....I kind of took the Glider approach when he recently replaced his bushings, but instead it was one beer per fastening hole, which added up to a lot of beer.....

How did the last hole after the last beer compare to the first hole and the first beer? Looking at it without a beer?

Well, maybe the best way to answer that is by saying the pan still leaks a little. But, at least I solved the stripped threads problem. Cheers!

Had the same trouble with the rocker covers on my Panhead. The front decided to leak 29 years after I rebuilt it. Oil leaked down on the front exhaust pipe and started burning. I stripped a couple trying to tighten them rather than remove the head and replace the gasket. I took it apart and Heli-coiled every hole.

Wow, looks nice! Looks like that was a lot of hell-coils you had to install.