I think the original poster means "V10" to be a R/V series truck.
I think they changed the model numbers in '86 or '87 from C/K to R/V.
Anyway, welcome to the SM465 club! I have yet to find an on-road use for first gear!
If 1st and 2nd were synchro, I would swap out the rear end to a 2-something ratio and drive it like a 4 speed instead of a 3 speed.