Bronc,
I am not exactly sure of what distributor you have, but from what you are describing it would sound as if you have unburned fuel. Are these blasts out the exhaust pipe or back throught the carb? Also do you have any type of electronic or High Energy ignition on that motor? Does this happen when you are acclerating, backing off, or just sitting still? Was the distributor a vacuum advance type which has been plugged off? Maybe a good idea would be for you to go to your local parts store and get the manual on that year Bronco. They have them at our Franklin Auto Parts here in Redding or did the last time I was in. I looked at some of them and they didn't cost that much and showed the connections for all the hoses and everything on the motor. If your center piece in the distributor is sort of in a star shape then you most likely have an inductive distributor. If you have the optical type, they normally either work or don't work. I know this isn't going to help a lot but maybe you can give us a little more information on just what is happening now and some of the really knowledgable guys will be able to help you.
Ron
