Ok so the truck is a 1977 f100 xlt ranger 2wd 351m c6. Yesterday I replaced the factory 2150 and intake with an edelbrock streetmaster 400 and edelbrock 1406 and a regulator set to 6psi. Neither was new but I rebuild the carb and sandblasted the intake. So at an idle all the way through the rpm range with out a load it is fine. When I punch it from a dead stop it is amazing(compared to the 2bbl but it won’t beat a new mustang off the line don’t ask how I know that lol) until 50mph or so and it acts like it is out of fuel and stumbles for a bit. Then I let off the throttle and let it smooth back out it is doing this every time. I should also add that unless I let it get all the way to an idle it will not stop sputtering. My first thought was the fuel pump went out but it was working yesterday just fine with the 2bbl. The last time it stumbled it backfired and blew a vacuum cap off so it ran real bad after that and I limped her home.
before

After

 

Did you verify float level setting during the carb rebuild?

I thought the 1406 was the electric choke version of the manual 1405 version, but I'm not seeing a cap. Is there a manual choke somewhere I can't see, or no choke at all?

Is it possible the ignition timing was changed during the intake swap (I don't know what level of distributor disassembly was required for that)?

 

The only thing done during disassembly was the wires removed and there is no choke on it. I found the issue to be the line before the regulator was pinched problem solved thank you.

 

Thanks for posting the fix!

 

Where did you connect the vacuum to the distributor to ? Looks like it's to an intake runner. It's meant to be run off ported vacuum.

 

I tried both no but no difference. I am running ported now.

 

If your running the stock fuel pump you don't need that regulator.