I don't have much to add, but it does sound like we are running a very similar carb. Mine is off a 1982 Ford E150 van. The first time I rebuilt it I actually took the tag into the parts store and they looked up the kit the old fashioned way... in a book. The Walker kit number I've used ever since is 15890. The carb has always run great minus a vacuum leak on the original install. Just in case you do end up back at the counter, it's an option if your using something else.

I believe the MC2100s are very forgiving and will run well even though you may not be running the same jets, adjustments as the next guy. For instance, I ran size 50 jets for the first few years. Plugs looked good and the exhaust didn't stink. But every time I mentioned it, I got bombarded with "dude you better jet down" comments.

I changed to 47s two years ago for a trip to Colorado and never put the 50's back in. It seems to run as well here now, and the plugs don't indicate a lean condition. It does run better at altitude though.