First, don't go peeling off the gasket from the bakelite vacuum interface spacer / heat shield. It's glued on, and all you'll have is a mess. Usually, it's not necessary to install any additional gaskets in between the spacer & manifold, or in between the spacer & carb. However, if you've stripped the emissions from the system, you may want to use the gasket provided with most carburetor kits that has no vacuum port holes in it. This gasket will effectively block off the ports from the carburetor throttle body, but some of the spacer ports will still function.

Generally I like to adjust the idle speed screw on a carburetor on the high side before I even install it. This way, I know it will run as soon as I start the car, but it'll be running on the main circuit, and not on the idle circuit. As soon as I start the car, I get out and lower the idle speed to something reasonable for engine warm-up RPM, like 2000 - 2200 RPMs. Then follow the idle tuning instructions found in the tuning section. You're looking to get the idle to 750 RPM.

Installing the carb is fairly straight forward. The Nikki is anchored down by four nuts. Once it's bolted on, the two most important steps which should not be done with a cavalier attitude are adjusting the throttle cable, and adjusting the oil metering pump (OMP).

Set the throttle cable so that when the gas pedal is fully depressed, the primary throttle valves are fully open (straight up & down). Be sure that there is a tiny bit of slack in the cable so that it is not causing a high idle by keeping the primary throttle from fully closing.

Adjust the OMP so that at 2000 RPM, over 6 minutes, the oil output is 2cc. In order to do this, it's obviously necessary to leave the oil feed lines disconnected from the carb, so while you perform the test, periodically drop a single drop of oil into each primary venturi at the rate of about 30 seconds.

Hook up the fast idle, and adjust the cable so that there is only slight slack. Remember, you don't want it to interfere with the idle. Adjusting the idle RPMs can be done by carefully bending the linkage very slightly.

Be sure the deceleration dashpot is adjusted properly and isn't binding. This can hang up the primary throttle shaft and keep the idle raised. If you have AC, adjust the AC idle compensation valve so that it raises the idle to about 850 - 900 RPM when the AC is turned on.

If after following the tuning instructions you believe you have a vacuum leak, follow the high idle diagnostics chart and instructions on the Troubleshooting section of my website.