Finding cast numbers is good, can you hit them with a wire brush so we can see them more clearly?

 

c5ta‑7505‑c

 

It says it's for a390 plus a bunch of other blocks for the t18

 

The motor on the oher frame looks like a 292

360, 361, and 390 all use the same block, your picture could be one of those.
Cast # for that is above the starter

 

I'm 100% sure that it's a 390 for the motor my dad was friends with the guy that built this which he is no longer around the guy that built it

 

It used to be an E-Class which is like back roads propane delivery truck

 

Well most of it LOL

 

Probably so, In the old days, we used the best we could get

See if you can find some #'s on the transmission
Rosco sells aftermarket parts, and helped don with his '56 project

 

E class?
you mean cab over?

 

E-class roads it's back dirt roads that normally don't get plowed in the winter

 

Bell housing marked: C5TA-7505-C is: 1965 F100/250 4WD; 1965/66 F350; 1966 F250 4WD all w/a 352.

"390" engine is a "combination of ingredients" aka a mutt, probably originally from a car.

Powered by Ford valve covers are 1967/71 car & 1967/76 F100/350. 1958/64 car valve covers have no holes for oil caps/smog valve.

Intake manifold with oil fill tube is 1958/64 car. Is it a 352, 390 or some other size?

On sale day, 352's magically become 390's!

What configuration was this truck when it drove off the assembly line?

Look on the left door face below the latch for the Warranty Plate, post the Warranty Number (VIN) from it.

 

It's not there I'm looking for the registration today

 

The most important numbers are the frame numbers. Post them first....

 

Looks like an interesting truck.