Hi, I am mostly on the 1948 - 1956 F1, F100 & Larger F-Series Trucks site but wanted to give you guys a shot at identifying an engine in an truck that needs rescued. My cousin is the brother- in- law of the guy who has the truck and he is down in Texas for the winter. My cousin remembers swapping it out to a 312 but I'm not familiar with that as a Truck Engine. Engines available for F600s in 1954 were the 115 HP six, the 130 HP V8 and the 138 HP V8. The 130 HP was the 239 and the 138 HP was the 256 cubic inch.

Now what strikes me as unusual as the dipstick is in the front. The 239 and the 256 have the dipstick more in the center.

I apologize about the picture quality. The hood could be lifted no higher.

 

Use the info from this site, Y to id the block and heads.

It has the 239 timing cover. The intake and exhaust manifolds also look like 239 parts. The dipstick is in the car location. A front sump oil pan would also be a clue that it came out of a car.
Possibly the intake, exhaust, and timing cover were swapped to a newer car engine. If it ran reliably with the 239 intake, then probably from a '55 or '56 car.