I had a 770 on the tired 440 in my Plymouth. It was pretty lean out of the box. It was a stock 350 horse engine with headers. I was up three jet sizes at all four corners and it was pretty close on the jetting. I can't give a really honest opinion because between the engine being tired and the tranny not holding at WOT, the car never impressed me. It most likely wasn't the carb's fault but expect to fiddle with it!