Crawl ratio question

[Wes Harden]

My son's f250 np435 4.56 and 37 mil tire, is ok to start out in 2nd, takes just a little finesse not to stall. 2nd could be 3.34 or 2.2 not sure which gear ratio in that one.

Sm465 is similar, I would expect 40's and 4.56 to be bit soft in 2nd gear starts

 

[sweetk30]

sounds weird but my truck is a k30 on 4.10 gear and 350 vortec -efi / th400 / 203-205 doubler and 255/85/16 = 33.0 tire skinny and she is like a farm tractor on the street .

so you with 40" tires and 4.10 gear i think it would help more with swapping gears deeper or swap doubler around . . . or BIGGER motor like a bbc for tons of bottom end power .