Hey Guys, I need some help. I have an 85 F350 Dually that I use to haul my 24 foot enclosed car trailer with my race car in it. I've been working on trying to improve the gas mileage on it. It has the original Motorcraft-Holley 4 barrel on it. It get 6.79 miles per gallon pulling the trailer fully loaded. I recently put a Quadrejet on it & the gas mileage dropped to 5.97 miles per gallon. I've been told to try an Edelbrock on it because I've had people tell me they did this on there trucks & it helped the gas mileage. What do you guys think? I called Summit & they recommended a 750 Edelbrock for it. I've had people tell me they get 8-10 miles per gallon towing with the same size motor & truck combination using an Edelbrock.

 

I replaced the original Holley 4180 (an emissions carb on my 1984 F250 Heavy Duty with 460 and 4.10 rear end...OUCH! BTW not worth working with) with a Holley List# 1850, 600 CFM vacuum secondaries that I reworked. Down jetted the primaries 2 numbers and up jetted the secondaries the same number. Installed two stage power valve and went one spring heavier in the vacuum secondary unit. Better than 1 mpg. To run the quadrajet you would need and adapter which just don't work well. I am not a fan of Edelbrock carbs, just too many things to adjust. I like the KISS principle when it comes to carbs.