The engine pad looks clean enough to see numbers if they were there...must like a replacement block.
Wire brush the top of the frame rail drivers side near the steering box. It will be stamped so you can read it while standing at the front tire leaning over the fender looking down on the frame. The stamping may be about 5-6" long from first to last number.
Got yourself a real Frankenstien Truck, lol!
Mike B
