Didn't Make It Home From Carlisle

oh wait; the engine is on the way out, the trans has as good as blown up, and the rear end is next. l have a complete drop-in powertrain, so gimmee that old girl cheap, and I will put a few more years on the chassis.
lol
oh, wait; you're in PA, that's a deal breaker, shipping would be killer.
lol
oh, wait; I am of course kidding.
My guess is fuel percolation, or a failing fuel pump. and the clanking could be the muffler dragging on the driveshaft.
Nice truck, no joke

Check your fuel line jumpers. If any on the Suction side have gear clamps, those need to be doubled up, and the screwheads offset 180 degrees.