OK. For those of you reading this for the Sniper Install.....I got it sorted out this morning.
First thing was adding the 25” battery cable from
@Fourrunner to reach the gear reduction starter. While I was on the positive terminal I redid some crappy terminal ends.
Because I was out of plugs, I had to drill a hole in the pretty new 60 series isolator to reuse a tube with a cap
Turns out, the adapter had slight clearance issues with the 1977 carb isolator so if you use the Mosley milled adapter then do yourself a favor and buy a new 60 isolator.
The isolator comes with a vacuum port in the base. It’s held in with some white brittle putty that screams potential vacuum leak. I trim it off so it won’t interfere with the throttle cable, cap it with a quality vacuum cap and RTV around it
No gaskets needed with a new isolator base. I did add a tiny layer of Indian Head to each side and to the threads of the screws going into the valve cover side of the adapter. Make sure the 3 posts are in the adapter before you bolt it all down to the intake
I install the sniper to the adapter using the supplied gasket dry on both sides.
Because I had the IAC out of whack due to the past vacuum leak, I could not “find” the recommended 2-8 while at 700 RPM
I used a method
@GA Architect had sent me a link to
Basically all you do is put a piece of tape over the IAC hole where I am pointing.
Use the IAC screw to adjust the idle 50 RPM UNDER target idle. In my case 650 RPM ensuring the truck temp is at least 160 degrees.
Turn off the truck. Remove tape.
IAC in the correct range and the Sniper worked its way to my target idle of 700.