my 75 highboy has a swapped in 390, 2bbl motorcraft carb on it. the ID tag is gone, but a mechanic friend says this is not the right carb, that it is for a small block. i am having a lean/hot issue at hiway speeds or under load.
so i was wondering if any of you could tell me what SHOULD be on this motor? ive done some looking, and im confused....1.08, 1.21, 1.23?? motorcraft? autolite? 2100, 2150, 4300??
as far as i know its a stock rebuild motor with stock intake.
thanks again as always

 

Ford Truck Carburetors


Just look for your engine, there will be a couple questions like type of choke and the like. I actually like the prices. Carb I want to use when upgrading to AOD was $500 at oreilly's, only $189 here.

 

First be sure your motor is a true 390, that is a lot of cubic inches for a 2bbl carb to handle. The only way to tell is either the VIN or measure the stroke. The original motor in my truck was a 360 and came with a 2 bbl motorcraft from the factory.

The 1.08 venturi was used on 302's and the 1.21 was used on the 335 series motors, or 351 based engines.

I dont think I would be too concerned with which exact product number that was on your truck, look more for cfm. If your motor truly is a 390, the more carb the better. Of course I would tend to say that for the 360 as well.

If you want to go back with a factory type unit, you cant go wrong with the motorcraft. Or, you can do what most do and find a factory 4 bbl intake or buy after market, upgrade to a 750 cfm carb and really wake up the torque and hp.