How did you arrive at the idea it is a '46 chassis?

3336704 is the format of a block casting number, not a stamping, However I can find no reference to that number.

Where did you find the 8PK110526?

"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.