don't take it for granted
i have a friend with 10 bolt front and rear. granted its a manual tranny but the gears are eithe 2:83 or 2:89 to 1 .....super high gears
i just swapped out axel in my '80 not to long ago and its auto i went to 4:10 3/4 ton axels and we checked the axels we pulled out and it was 10 bolt front and 12 bolt rear and it had the exact same highway gears as my buddies and it had what was a gov lock in it and his was open so i let him put the rear under his since it was locked and was a 12 bolt and his wasn't locked and only a 10....
only blazer i've seen yet that had 3:73's was my stock '69 axels..
i had a 75 model that had 3.42"s and i swapped it for 3/4 ton axel with the same gear ratio and had 38.5's with standard trans and 205 i could put it into granny on the tranny in 4 lo and had all the gear i needed sometimes it was to low to clean out tires so i usually used second or 1st past granny however you call it with transfer in 4 low,,,
i'd get out on hiway rollin about 60-65 and the 38'5 with the 3:42 had motor running about 1200-1400 rpm and 21 mpg it had stout small block in front so it wasn't lugging but once you got it up to speed it took very little to keep it there.at 50 truck was almost at idel..i miss that truck
