Narrow Dana 30's

If I want to do a swap from the 27 to a 30 what years am I to look for?

 

Depends,
If you want drum brakes 1972 through 1975 are possibly the best with 3.73 as standard or 4.27 as optional final drive.
In 1976 3.54 becomes the standard final drive while the CJ disk brakes begin in 1977.

 

When did they go to the wider track?

 

I think the wide track came in 81 or 82. ive never used one but hear the tubes bend easy

 

I used a '73 D30 and did the disc conversion. essentially the same as converting a D27. I wanted the 6 bolt hubs. Sometime early 80's Jeep "improved" the hubs to 5 bolt. Wonder how much $ they saved on that "upgrade".

 

The 1976 and later D30's have a strange little flat cast iron extension plate on the outer portion of the carrier located near the pinion input.
I suppose that extra casting extension functions as a suspension limiter ???
Anyone know of its purpose ? It's been many years since I drove a 1976 CJ.

 

I used a 73 D30 in mine. I converted it to disks using 78 brake parts. This way I have the 6 bolt hubs and also the thicker disks. IIRC 78-79 used the thicker disks and 76-77 used the 7/8 thick disks. I also had to use 5* caster shims made by Mcruff to correct the caster.

I'm very happy with the setup. Bearings, seals, and brake parts are available at nearly every parts house around here. I put in an Aussie locker and haven't looked back.

 

'76 was drum and '77 was the thick discs as an option iirc. I know '80 and newer were thin discs. I want to say late '79 were also the thinner discs but not 100% sure on that.

 

I knew that I had the dates mixed up

 

Actually, 5 bolt started in 81. 80 models were 6 bolt hub.

 

I used a '76 on my '71. Kept the big drum fronts and put the 11X2's in the rear, works good! That extra piece on the diff is an oil and junk collector, does anyone know if it's possible to drill a drain hole in it? Oh, I had to change 3.54 to 3.73 cost for a new carrier too.

 

That extra piece corresponds with a bracket and rubber bumper on the OEM application. Helps keep the axle housing from hitting the oil filter on V-8 models. Do what you want with it.