question about my 72 burb

[WOLFMANmike]

i have a 72 burban 3/4 ton i was wondering in anyone knows what the most common gear ratio is in the burbs back then ? i know originally it is a small block burb and its a 14 bolt floating axle rear end .. dont know if this info help you help me or not ? but im looking for a way to know what it has now and what i can change it to to get better MPG out of it lol i know mpg thats funny with such a heavy beast but im sure i can pull some out of it somewhere

ty in advance for any help you offer me

[Street Smart]

Welcome to the board!
I`m not a 3/4ton guy, but every C10 I`ve had came with 3.73 to 1 ratio. I`m sure someone with better info will chime in.

[bigpapinkc]

my burb came with a 4:56 but it also came with a4:10 eaton

[vectorit]

Hard to say, since your rig did not originally come with a 14 bolt.

Take a picture of the axle differential cover for us, just to make sure there is no misunderstanding.

[WOLFMANmike]

Originally Posted by vectorit

Hard to say, since your rig did not originally come with a 14 bolt.

Take a picture of the axle differential cover for us, just to make sure there is no misunderstanding.

lol that's a good idea ... i don't know why i did not think of that before i will post a pic tomorrow to dark now ty for all your help

[gearboxx70]

Depends on the engine it rolled off the line with too. Mine is a C20 with a 292. I think it originally had 4.11 or 4.56 gears. The engine would scream at 50 MPH with the stock gears. Now I have a 12 bolt from a '78 pick up with gears in the low 3's (don't remember the exact ratio), and can do 70 when I need to. I just don't have enough power to get out of my own way now.

[WOLFMANmike]

heya guys i wanted to apologize for not putting up a pic today i had a very busy day and just couldn't get it done but i will tomorrow ... i just dident want you guys to feel like i was wasting your time or info

[WOLFMANmike]

ok heres the pics i hope they help

[vectorit]

That is an Eaton axle, and being 3/4 ton probably has 4.57 gear ratio.
Check the bolts for a small tag attached, hopefully it is still there and it will give the gear ratio info on it.

[WOLFMANmike]

so what would you all say i could drop down to to get some better MPG and drive ability out of it ? on the freeway and in town like 3.08 ? or ?
just so you know ill not be wanting to tow with it im looking to just get a good cruiser out of it

[vectorit]

I would look for a newer axle, and have it set up with the gears you desire.
The Eaton's are great axles, but the gear choices are slim.

Keep an eye out for a Dana 60, that way it is still 8 lug and full floater.
Plus the D60 is lighter than the Corp14 set up, but the choice is yours since Corp14's will probably be more common out there.

[AzDon]

Why guess about the ratio? It's easy enough to figure out...
Draw a line with a large felt pen on the pinion yoke and housing where you can see it crouching next to the truck. On the same side of the truck, put a mark on the tire at the very bottom. Have somebody drive the truck (forward or back) for one complete rotation of the tire and count the number of turns of the pinion yoke....
You will probably get either 3 or 4 full turns and a partial turn which will get you close enough to guess which ratio you have....
If there isnt a good sight line under the truck you can instead put a large zip-tie around the driveshaft and point the end at the ground when tightening it and count the number of turns that way...
Both rear tires need to be on the ground rolling in a straight line to eliminate the spider gears from fouling the calculation...
My 68 Burb figured at about 3:1 (likely 3.07:1) which I'm told is not uncommon in a c-10 Burb

[POS1]

I think mine is a 3.73. It's a great ratio for getting moving while still highway cruising without high rpms.
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[Yerboogieman]

I was told I have a 4.11 with Detroit lockers. That, paired with the TH350 equals not the best fuel mileage. I chirp the tires around corners all the time on accident.

[jeremiah king]

keep an eye out for a swing dana 60.

[Bigdav160]

Delete post

[68 TT]

Originally Posted by Yerboogieman

I was told I have a 4.11 with Detroit lockers. That, paired with the TH350 equals not the best fuel mileage. I chirp the tires around corners all the time on accident.

If you do have the 4.11 gears and a locker in the Eaton HO52/HO72 rear end that is about as tall as you are going to find. Most were 4.57 or numerically higher. I understood there were 3.73's available but I have never seen any for sale ever.

The gears and parts for them are quite hard to come by and relatively expensive. You can sell your 4.11 gears and locker for more than what a whole 14-bolt would cost you to pick up and rebuild.

A 73-98 14-bolt is easy to come by and can be had with 3.73 gears quite often and have even taller gears available for them. Unless you have leaf spring rear suspension you will need to add trailing arm perches to it and run an aftermarket track bar / panhard bar.

The locker in your Eaton will fit into the 14-bolt carrier if you want to upgrade a non-posi 14-bolt.