I've been reading (too much) about updating your 1 bbl to something different. What I have come up with, from this forum is a few things.
Assuming that you have a stock engine, aftermarket intake and the EFI exhausts, going into a single 2.5" without a Cat and maybe with a muffler of sorts.

What I seemed to get was the Edelbrock 500 was the best choice, the Holley 390 was next and then there was some mention of a Motorcraft 2150 2bbl or a Quadrajet.

After reading all of this, I am not sure the route I will take. More than likely the 2150 for now. If things dont work well, then a 4bbl might replace it. The bottom line is achieving the best mpg/power ratio.
A thought, are there any performance 1bbl carbs that could work for this as well....or is there no such thing.

Has anyone thought outside of this box....and been successful?

 

i used a holley 390 its okay but i think i have something wrong as it wastes more gas and feels heavy.

 

I use the 1 bbl off of a mid 80's mustang 4 cyl. seems to do fine and easy on the fuel.

 

Have you done this yet? Do you need to change your intake manifold for the Motorcraft 2150 2BBL?

 

Iv'e reasearched this for a long time now. (and I still haven't got a round to buying one ) From what I have found is that the best choice for a truck is the holley 390 and the offenhauser dual port manifold

 

is there something better then the holley 390?

 

The answer to that depends entirely on what else is being done to the engine. I don't pretend to be an expert, but here's what I have gathered from reading messages here over the years. The first thing to understand is that you have to think about the entire engine as a single system. Slapping a huge intake and carb on an engine with the stock log-style carb exhaust manifold and stock cam with no internal changes won't give you good results.

An engine that is stock internally but to which a set of EFI exhaust manifolds have been installed along with a low restriction exhaust system would probably do quite well with the Holley 390 on any of the aftermarket 4 barrel carb manifolds out there, with perhaps the Offy DP being the ideal match. Another good choice might be the Clifford model 43-4502WH with their model 08-1013 two barrel carb adaptor and a 2 barrel carb of the sort often found on some of Ford's small block V8 truck engines. An engine set up like this will have a smooth idle and if it's set up properly and driven conservatively it could actually get slightly better gas mileage than a stock engine.

Upgrade the cam to one designed for "RV" use or for "towing" (which focus mainly on boosting torque in the low RPM range up through the lower half of the midrange) and boost the compression ratio slightly, however, and the Holley 390 or perhaps a slightly larger 4 barrel carb with either the Offy DP or one of the single plane manifolds (Offy C or the Clifford model 43-4502WH with their model 08-1014 four Barrel carb adaptor) might be good choices. Shorty headers might be considered at this level as well, but I think most folks here would advise the EFI exhaust manifolds because they cost less, are likely to be leak-free and will last as long as the rest of the truck. An engine set up like this will have a smooth idle and if it's set up properly and driven conservatively it should have about the same gas mileage as a stock engine.

Upgrade the cam to something oriented a bit more toward broad mid range torque and less toward low end torque, boost the compression a little more (perhaps into the range where you might be using gasoline of the grade that is midway between regular and premium), and do some mild port work on the head and you'll probably want to think about headers (shorty headers would be fine at this stage, but full length headers would be an option, too), as well as a carb rated for 500-550 CFM or so on either an Offy C or the Clifford model 43-4502WH with their model 08-1014 four Barrel carb adaptor. An engine set up like this may have a slightly lopey idle (depending on just how radical the cam is) and it's probably going to get somewhat worse gas mileage than any of the previous stages.

Upgrade the cam to something oriented more toward upper midrange torque and high RPM horsepower, do some serious head work, boost the compression ratio to something that requires premium fuel and install some full-length headers and your induction system choices start to get a bit more exotic. You could be looking at a single 4 barrel carb in the 550-650 CFM range (which would probably be the easiest to set up and tune) or perhaps multiple smaller carbs on an intake like the Clifford model 43-4650 Dual Quad Intake Manifold using either their 4-barrel adapters and two small 4 barrels or their 2 barrel adapters and two mid to large 2-barrels, or perhaps one of their manifolds designed for triple 2-barrel carbs. Anybody who decides to go with 2 or more carbs should be prepared to spend some serious time or money (or both) getting them tuned properly. An engine set up like this is likely to have a distinctly lopey idle and it's probably going to get terrible gas mileage.

Most folks who come here to talk about building up their Ford 300s seem to go with one of the first two lower level stages described above, mainly because they plan to use the engines in trucks doing things people do with trucks and not in hot rods, but also because it costs less than the other options and they don't want to destroy their gas mileage or have to change to a high-stall torque converter if they use an automatic transmission.