Rearend , What to do??

[Megaton67]

i'm working on a 67 1 ton dually, can any one tell me what duall rear ends will bolt up DIRECTLY if any. the one in it is a corp. 10 bolt and is in great condition, the only problem is the 4.56 gears that are in it. looking to go a little higher. thanks for the help.

[Longhorn Man]

you can get a 4.10 gear drop out, it comes right out like a forn 9 inch. Pretty much any small block with an autoimatic 67 - 72 3/4 ton or one ton will have it unless otherwise optioned.
Otherwise, the only DIRECT bolt in, would be the Dana from the same years trucks, and I'm not certian they came under DRW trucks.

[Megaton67]

i'm assuming the axle and pinion splines are the same??

[Longhorn Man]

yep.
The 3/4 ton had the HO52 Eaton with in the corperate housing, and the one tons had the HO72 eaton in the corperate housing. Direct swap for one an other.

[1969 GMC]

Originally Posted by Megaton67

i'm assuming the axle and pinion splines are the same??

No they aren't, the Eaton rear you have under your truck has coarse spline axleshafts and pinion gear. IIRC its 17 on the shafts and 10 on the pinion, but I could be mistaken.

The Dana 60 Longhornman refers to has 30 spline axleshafts and a 29 spline pinion gear, so you may have to get a new driveshaft yoke if you use one of these (if that is what you were wanting to know). Also, the Dana 60 isn't a factory DRW, I don't know if that would cause you any problems. EDIT: I see you meant the 52 vs. 72. My mistake!

Personally, I would recommend a 4.11 chunk for your axle, or one of the harder to find 3.90 aftermarket units. If you really don't want to use this axle and have your mind set on higher gears, swap in a 14 bolt out of a newer truck. You might have to do some cutting and welding of spring perches and shock tabs, but IIRC the 3/4 ton 14 bolt has the same spring spacing as the 67-72 1 tons (could be wrong about this also). You can gear a 14 bolt up to 3.23.

[Olden Days]

I swapped in a 14 bolt dual rear end from a late 70's to my 70 C30. The only mod I had was shock mounts. spring spacing was the same.

[Megaton67]

thanks for all the help. i guess now the parts search is on!! still open to anymore ideas. the more brains the better.

[Yukon Jack]

Will you be needing a cab and chassis rearend which is narrow or the wide type that you would find under a pickup bed with flares?

[Megaton67]

a narrow one. its a cab and chassis truck. how late of a 14 bolt will work, or will any 14 bolt work??