Hi all, new here and first post. I have '78 F150 4x4 project truck with a 351M. When accelerating uphill or under any kind of load, the gas pedal will "click/snap", depress quickly and the engine sputters. If I let off, the engine catches back up until I accelerate again. It's very quick, but the engine loses all pull when it happens so if it happens a few times, I'll lose all acceleration. It's been a little concerning on the highway a few times.
Any advice/input greatly appreciated.
Thanks.

 

Look under your dash and see if the pedal is hanging up under there. If not, open the hood, remove the breather and actuate the throttle from the pedal 'linkage' at the firewall end of the cable. See if there's any problem there.
You can also detach the cable from the carb ball-stud, and isolate the hang-up.

But it might be the cable itself - if some strands break, especially near the ends of the insulation, it will hang-up and then over accelerate as it breaks free.

And welcome to the site! How 'bout some pics of your rig...