The variable venturi carb worked good when it worked as I had a 82 F250 with it on a 351-w C-6 and 3.50 rear and it got better gas mileage then my 87 F150 with a 351-w C-6 with a holley 4 barrel and a 3.08 rear. It got to where sometimes when I hit the gas it would bog bad and no one wanted to work on it so off it went.