[longhornchris04]

Definitely sounds like running rich. I've got a '79 that did (well, sort of still does) the same thing.

I'm not sure what changed - odds are you can adjust the mixture screw on the fuel distributor a bit leaner than it is and correct most of the issues, certainly the warm running performance. All you need for that is a 3mm hex key and some patience. Make a small adjustment, drive, pop the clutch, and see if the RPMs fall "too far."

Of course, the "right" way is to ping Tony and check everything. While its clear your mixture is off, there are a number of other CIS components besides the mixture adjustment that could be set or operating incorrectly.

Oh, and weather permitting (because mine doesn't go out in the rain), I could help in person - I'm in Beavercreek. Send me a PM if you want to meet. I have the tools necessary to adjust idle and mix in my car.