Supposedly it's a rebuilt Rochester Quadrajet. I just bought the car yesterday, and with life and kids haven't had a chance to research part numbers and all that jazz. I was planning on doing a quick tune up on the carb tomorrow afternoon to see if that smoothed things out before I start diving deeper. I did buy the car knowing it had an exhaust leak, so there could be vacuum issues I guess. Other than the stumble on light throttle issue, the car seems happy.