i have a 76 F-150 with a 78 460 in it. when i first put it in it only got about 8 mpg with the stock motorcraft 4bbl on it..... it had no torque and run crappy.. i bought a 780 vac sec holley and tweaked the timing a touch... now i get between 12 to 15 mpg as long as i keep my foot outta the pedal.. and there is plenty of torque for whatever i need to pull... i made no other mods to the motor but the carb... no one believes how much torque it has till they drive it... then their opinion changes also i only run premium unleaded.. regular unleaded makes it run rough...

SwOkcOffRoader
1976 F-150 460 780 cfm Holley 780cfm 4bbl "Hot Rod"
1978 F-250 snow commander 1 ton 4X4 351m 500cfm 2bbl 35" tires "Big Daddy"
1978 B-700 Bus 389 industrial block 4bbl holley 10 speed