Hi Mike, if it were me, I wouldn't try to re-invent the wheel. Keep the original engine/flywheel/clutch/tranny combo and rebuild as needed BUT use a new or re-man starter that was designed for that truck, just my 2 cents.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy