It's s 4spd car ... so, when I first got the car out had a street avenger 770 on it. Ran great(at least I thought so). Drove it that way for 5yrs... fast forward to the 383 build in my coronet, was having trouble with an edelbrock 800avs. Put that 770 on that motor and there it stayed ! I built an AED 750dp and have had a stumble ever since. Accelerator pump circuit is good, very crisp off the line.. it's part throttle acceleration that's killing me... stumble stumble stumble go ! Drove with a vacuum gauge, played with power valves, up the primary jets a few times and got better but still there ..... it's in the primary side, all my testing done with secondaries disconnected... I've always felt the car was over carbed, even with the 770..... Guess I'll find out soon !