Ready to shoot my 273

I'm at my whits end concerning my 67 Dart with a 273/904. Engine & tranny have 30-35,000 miles on a rebuild previously done before I got the car, it also has been upgraded to electronic ignition and the regulator has been changed to one for the electronic ignition. I've put on a water pump/had the radiator rodded out about 5 years ago and just recently had the 2 barrel carb rebuilt, I also dumped the single field alternator and put in a duel field one for a 73-74 duster. I grounded the second field post. Here is the problem: The car starts and runs ok, it's when I have to come to a stop the engine idles down and some times will stop. With the engine hot it takes a couple of tries before it will start again. The engine also hesitates when I give it gas, but only when I'm driving, with it parked and in Park it takes the gas with no problem. I've advanced the timing and the engine runs good while idling, but when I put it in Drive it idles down and almost seems to want to stall out. Can some of you small block gurus give me some advice as to what I need to do. I really hate to have to spend money that I don't have and take it to a mechanic. Any help is appreciated. If what I wrote above doesn't make sense just let me know and I'll try to make it clearer.

Dan in Silicon Valley