CFI to carb conversion question

[StockerStang]

I have an 86 3.8 CFI/auto and am sick of the CFI. This car only has 98,000kms (55-60,000 miles?) so I was trying to keep it original or original looking. (that's why I'm not dropping in a 5.0 or 5.8)

So, plan is, pull the CFI and bolt on a 1.08 or 1.21 2bbl carb. I am planning on connecting the two fuel lines together to run all the fuel back to the tank and tap into that for a couple psi of fuel pressure. Block of metal with the two different threads in it to bolt the fuel lines to, then have another port I can add a regulator and gauge and then run the line to the carb.

My question is, has anybody ever done it this way? Any idea where I could get a block to connect the fuel lines to or will this be all on my own. Searched everywhere on here and while I did see some CFI conversions, they are all 5.0 for one and two, they pull the intake off and add a carbed intake and carb...that's simple but not what I want to do. I'll use the original air filter housing as well.

Depending on how this goes, I might add a 3.8 supercharger from a pontiac and a 4bbl, but this is not a hotrod, it's a cruiser. (antique plates)

Anyone know what the thread pitch and size is for the two fuel lines?
Thanks

 

[Noobz347]

You will need a fuel pressure regulator (return style) that drops the fuel pressure down to roughly 8 psi for carb.

The alternative would be to run a different style pump for carb.

 

[StockerStang]

Yeah, that's what I was thinking, I'm just curious what the thread size or pitch is for the two fuel lines that bolt into the regulator/cfi unit itself. I guess when I did in to it I'll figure that out. Just wondering if anyone has done it like this, pulling the cfi and bolting on a carb to the same intake. Maybe I'll be the first? LOL!

 

[Noobz347]

Yeah, that's what I was thinking, I'm just curious what the thread size or pitch is for the two fuel lines that bolt into the regulator/cfi unit itself. I guess when I did in to it I'll figure that out. Just wondering if anyone has done it like this, pulling the cfi and bolting on a carb to the same intake. Maybe I'll be the first? LOL!

Yes. It's been done. Ford even had a conversion kit available at one time with all the pieces and parts (it could have been FMS and not Ford but anyway).

I don't know the answer to your thread pitch question but I [do] know how you can find out:

https://www.amazon.com/ChgImposs-Imperial-Whitworth-Industrial-Measurement/dp/B07J9V9JTK?sr=8-1

Just takes all the guesswork out

 

[StockerStang]

LOL, yeah I have a thread pitch gauge. Once it gets a bit warmer I'll get at it. I'll do a full video as well, depending on how the white mustang (U/SA) runs, I'll see if I can get the blue one (with the 3.8) to the track to see the difference.

 

[rotorhead22]

You will need a fuel pressure regulator (return style) that drops the fuel pressure down to roughly 8 psi for carb.

The alternative would be to run a different style pump for carb.

I'm in the process of finalizing parts for my 89 5.0 and was curious about the return to tank, If I'm removing tank pump and using a pickup with low pressure external pump, there's no need for a return line is there?

 

[Noobz347]

I'm in the process of finalizing parts for my 89 5.0 and was curious about the return to tank, If I'm removing tank pump and using a pickup with low pressure external pump, there's no need for a return line is there?

It depends on the style of pump that you use but in most cases, that is correct.

There are carb systems out there that use return style fuel systems but I think they are few and far between (mostly racing).

However, if you use an external low pressure pump then you are correct. So long as that pump is for the carb setup you are putting together, it should be fine.

 

[AeroCoupe]

I know you can run returnless with a Holley Blue pump. My buddy did it for years however he just recently converted it to a return style and the pump is 10 times quieter and the carburetor seems to be a lot happier.