I have a 351 Modified that will start up but not stay running, It seems like a fuel delivery issue but I am not sure. I've not worked on a motor older than 1987.
See that's the thing, I can't get it to stay running long enough to warm up. It acts like it's not getting enough fuel. Are these motors supposed to have fuel pressure regulators? I'm not sure. I'm new to the Ford scene. I'm used to working on Mopars.
There is no pressure regulator. You are limited to whatever the fuel pump produces, which is typically 5 psi +/-. What is the condition of fuel pump, fuel filter, etc.?
If it warms up just fine, I'd doubt it's the fuel pump, but pull the line off at the carb, turn the truck over and see what kinda flow you're getting. Otherwise I'd start thinking vacuum, choke or floats.
I'm also having an issue since this motor came from a 79 F-250 and was put into a 86 F-150. I have it able to run as long as I have my foot on gas. But it doesn't idle under its own power and I don't have any alternator wires for the motor. I had someone suggest using a one Wire alternator but I have no clue how to go about that or what one to get.
I don't know what else might be causing the issue then. unless the fuel pump is malfunctioning. but the inline filter is filling up like You would expect with the fuel pump functioning properly.
its a holley 4 barrel with a tag from MotorCraft but i'm not seeing anything else to identify. I've been thinking of an EdelBrock for it. Its got so many issues in it already. its a 79 351m bored out to 400. that was placed into an 86 F150.
sounds like you have a holly 4180 which would have been a factory ford carb and are a bit different then and aftermarket holly 4150 or 4160.
how much do have to open the throttle plate to keep the engine running? did you re build the carb or had is been sitting?
if the floats are set right, and you have good fuel pressure, no noticable vacum leaks (unplug and cab all holes on the carb just to be safe) https://www.youtube.com/watch?v=ge-mIk6nEYQ
the idle fuel circuit may have an issue and opening of the throttle plate will open up the transition circuit to get fuel. adjust idle mix and see if this helps and or tear down the carb and clean.
I really have no idea about anything on this truck. I bought it off a friend who was got it the same day he sold it to me. I'm pretty sure the motor sat and I'm also sure that nothing was changed on it once it was put in the 86 body. Its a whole mess of headaches but once I get into it, Itll still be a great truck.