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.....
