Hello, I have a 1985 f150 2wd with a 302 and a 4 speed overdrive rts manual, it has the c ratio for the gearing and 3.27s in the rear, I have a 2150 2bbl on the motor, it has been bored 30 over and a mild cam apparently, this is how I bought the truck, but it gets very poor mpg I daily it to work which is about 20ish miles one way, any advice would be useful, I was thinking about doing a 4bbl swap

 

What is your mileage. If you are getting around 15mpg, you are doing good.

 

Avg of 15 is what Mt 81 F100 with a 300 six and granny 4 speed and overdrive with a 2.75 rear gear.

Yes what are you getting now for MPG?
Also install a Air Fuel Ratio gauge as it will tell you if running rich or not.
Dave ----

 

I am currently getting roughly 7-9 mpg if I was getting 15 then I’d be real happy

 

What size are the tires? Where is the ignition timing set? What kind of exhaust does it have?

Many factors play into fuel economy. We can't tell you what's wrong. We can Only guide you in the right direction to make improvements

 

7-9 mpg is extremely poor mileage indeed. The 2150 carb came in two types, feedback and non feedback types. Many people have reported poor mileage with the feedback carb. For comparison I ran a stock 350 GM engine in a 73 half ton pickup with a 2bbl Holley and consistent 18 to 20 mpg. No smog stuff, straight stock, dual exhaust.

I have a feeling that your issue involves the feedback carb that is no longer under control. Either that or a fuel leak. 15 mpg should be easily obtained with a 302.

 

Something is going on here. 1985 should have a fuel injected engine. I wonder what distributor he is running. He said the engine was rebuilt but sounds like there has been lots of modifications. It would be interesting to find out what exact carb and what ignition system he is running.

 

85 is a split year.
Early models had the feedback carb and late had the fuel injection.

 

Also....
a 4 speed overdrive rate manual, it has the c ratio for the gearing and 3.27s in the rear
Can't say I have ever heard of that.
If he has the AOD and somebody swapped the feedback carb, did he get one for the AOD and have the linkage adjusted properly?
Has he done the DS2 swap?
If not, and still running the stock dist., then it is probably in limp mode.

 

i have a manual lol, it has the rts 4 speed manual, it’s a factory option, the 3.27 rear wasn’t stock to my knowledge.

 

235/75 r15, the truck is just about completely stock, and my truck was a factory non efi in 85, the emission equipment has been removed from the truck

 

I have stock ignition system for a 1985 f150 with a carb, in 85 it it was a split year, to all of my knowledge the motor has been bored out and a cam has been put in it, if it has one it is a very very mild, I’m also still running the stock icu for my Timing, it is a brand new motorcraft unit.

 

my carb is not a feedback it is a non feedback there is zero wires running to or from the carb, there is also no connectors on the carb it’s self, I have my Electric choke hooked up right too, now to my knowledge this isn’t a factory ford carb and one of the cheap 2150s off of Amazon, that could the be the issue

 

I would suggest putting a timing light on it per the instruction label on the radiator support. See where it is set and if it advances. If it has TFI, ECM controlled ignition it may very well be stuck at base timing. That's easily a recipe for 7-9 mpg.

Proper spark advance might wake up the "mild" cam.

 

I have the stock ICU unit in the truck, it’s not the original it’s an official motorcraft replacement not a cheap knock off, I also have a brand new distributor and if ignition coil, the truck runs and starts beautifully, but I’ll put a timing gun to see and get back to you, thanks