2 to 4 barrel? 74 f250 390 fe
I have a 74 f250 with 390 2 barrel holly I wanna upgrade to a 4 barrel and mild
performance intake with out jeopardising much on mileage what do you
If you drive easy, a four barrel carburetor will bet better fuel economy than a two. I think it's a good idea, but you'll also have to replace or modify the air cleaner to fit the larger orifice. Linkage modification shouldn't be difficult..... I'm glad it's a "74 and not a "76 that would get into smog test problems.
Use a small 4 barrel not too much bigger than the 2 barrel. Summit racing has a 450 CFM carb with vacuum secondaries that they sell as an economy carb. I would try the carb first before you upgrade the cam.