I have a 78 Ford Bronco with 351 Cleveland and a 2 barrel carburetor. I I am having issues with performance and idol. When I get the truck to idle and drive I have no performance and cannot excelerate hard. When I get the performance I want it floods when it is at idle. I have had the carburetor rebuilt, put a new fuel pump on it, new fuel filters everything and I can't get it to level out for me. Any pointers?

 

Kind of sounds like it's running rich. Did you tune the carb yourself? Or do you have any knowledge about tuning one of these? Also if you know what carburetor it is that might be helpful. I am thinking it will b the stock 500 CFM 2 bbl that came in these trucks but you never know.

 

Make sure the float is set right. Not that it matters buts probably a modified not a cleveland.

 

I was going to ask/point it out but figured I wouldn't bother. Unless someone put a C motor in, it is a Modified. Modified is a cleveland block & heads with some Windsor guts. Often dubbed the "Mutant" as well.

 

Uh, where did you pick up that info?

The 400/351M is NOT a 351C block. It is a different block with a higher deck height. The heads share the C design up to a point, but are different castings. Windsor guts? No. The 400 crank can be modified to fit a 351C or W, making them a 400, but there is no direct interchange.

Also, the stock 2bbl carbs were not 500 CFM.

To the OP, you can get rebuild kits for these carbs easily. They are simple enough and easy to rebuild--follow the instructions etc.

BUT as suggested, find out which carb it is. Look for numbers cast into it and look for a clock-looking mark with a number inside like "1.23" or "1.08". More on Ford 2bbsl here:

https://www.ford-trucks.com/forums/1...eral-info.html

And from that forum, this:

Motorcraft 2150 2V Carburetor

Nice pic of the 2150 carb right up front to help ID it--BUT WAIT, THERE'S MORE!!!! Click on the rebuild link and Bubba damn near comes right out of the computer screen and rebuilds that carb for you!!!

 

I got it here. Mine has the Modified.
If this is incorrect then sorry, but it's what I dug up when I got my 78.
Site link. http://en.wikipedia.org/wiki/Ford_335_engine
It is mentioned that they used the 400 block and milled it down BUT they mentioned a C block and heads with a Windsor crank. The crank was what I ment by guts. I was a little vague, my bad. The 351 can be modified with longer connecting rods to be made into a 400.

As for the Carb, I had the 2150 and had been researching it for tuning and knowing how it worked. I read somewhere that it was rated at 500 CFM but I cannot find it anywhere So, I guess I read wrong. For the 351's they were rated at 351 CFM apparently. Maybe I just got my Carter and my Motorcraft confused, who knows. Honest mistake.

 

Not to beat a dead horse--or in the case of a (stock) 351M, a dead dog, but:

First, beware Wikipedia. There are many errors, and, as in this case, they have some info right but fail to explain fully.

That would be the case where the 351w vs 351m cranks are concerned. They are very similar, and will "bolt in" in each others place. But the crank snout is different on the m, and balance is probably different too. They are certainly not the same part.

There is no such thing as milling down a 400 block to make anything other than another 400 or a stroker, with a very small amount milled. Milling an inch off it makes it scrap. Besides, the 351C was introduced before the 400 was introduced. Again, the blocks are based on many of the same numbers, but are completely different castings.

Ditto the heads--same design, different castings.

As for making the 351 into a 400 with longer con rods....no. First of all, the 400 came first. The 351M is a shorter stroke motor, so the crank and pistons are changed to make a 351m--thus, the crank and pistons must be changed to make a 400 out of a 351m. Rods stay the same, if you like them.

As for CFM ratings, they are in the link I posted above. The highest is 424 CFM, and there is a 351 CFM version.

Usually a 500 CFM 2bbl is a Holley 2300 series carb. Can't find any Carter 2bbl at 500 CFM. Might be one, might not....

 

Going past the carb issue, that seems to be covered, have you checked out your vacuum advance?

 

Are you thinking vacuum leak?

Carb to spacer, spacer to manifold gaskets are suspect. I had to use two to soak up the irregularities in my spacer on my '65 289.

Who rebuilt the carb?

 

I have a 96 EFI engine so I try to stay away from carbs.. they make me too fat.

Anyways Bearoth, did you every get your Bronco running right?