help me pick gears

[eray92]

motor: suppose to be a 383 only thing I know for sure is 350 block with 305 heads, performer intake, q-jet, summit headers with 3" collectors, 3" exhaust with flowmasters, stockish sounding cam,

transmission: 200-4r with stock torque convertor from 87 caprice

tires: 255/45/20s 29" tall

truck: 82 chevy custom deluxe swb no ac, manual windows and locks, power steering and brakes

gears in it now are 3.08s, I have some mint 4.56s laying around.

truck is used to drive to work (5 miles away) and to just drive. something about the sound of a sbc

I do not drive it on the interstate, only state highways and county roads, speed limits are 55

with 3.08s rpms @60 are around 1350 locked up tc
with 4.56s rpms @60 would be around 2000 (idk if the online calculators account for the lockup tc)