It is very strange for a 100 series to have 8-lug wheels. My guess is someone put a 100 cab on a 150 truck. Is this truck a long bed? A 101 is a half ton, 114" wheelbase, shortbed. A 123¼" long bed half ton would be a 102. Three quarter ton trucks were only available in the 123¼" configuration, designated 152.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.