72 Duster Resurrection

moparmat2000 said
My shop is a pole barn. Cheapest way to build one if your city allows it. Poles are 4" square tube 3' deep cemented in. Then welded the framework to them and sheetmetaled it. I used the sheetmetal walls as a permanent concrete form, and only framed out for the roll up door, and people door.

Where the framerails go from angled down to flat, just a bit behind where your jack is at. Is good.

At the rear set them just fwd of the leafspring front eye on the flat of the rear framerail.

Your pic w the tape measure looks like 4.50" to me. So you prob already have a big bolt pattern rear axle. Try to bolt your small pattern front wheels on it. I bet they dont go. Another easy way to tell is try swapping the lug nuts. Small bolt pattern is 7/16" large bolt pattern is 1/2" your front lugs wont fit the rear, and the rear lugs will be swimming on the front studs.

Thats another good reason your doing the BBP disc swap. If the rear is already BBP, and front is SBP you gotta carry 2 different spares or you got a 50% chance of being screwed if you get a flat.

As i said, even the 7.25 could come as a BBP axle. The tube diameter and cover shape will determine if its a 7.25 or an 8.25. I will try to find and post a cover identification chart for you. I bet with your way of measuring, and getting 2.60" thats close enough to 2.50 that its prob a 7.25 rear. You can also measure the width of the U bolts at the spring plates. If its under 3" you have a 7.25" and still thats not bad. The brakes from the backing plate out from that will swap to an 8.25, and 8.75. So even if you redo the rear drums, you can move them to the better rear later, and you can get your wheels squared away where you only need 1 spare.

As said earlier if its an 8.25" its a keeper. Gears, and sure grips out of dakotas, and jeep grand cherokees with the 8.25 will fit. The jeep with a sure grip being way easier to find as it made it better for offroad, and with 3.55, 3.73, 3.90, and 4.10 ratios.

Yeah a real shop is on my wish list. I've already called around to builders. A pole barn is indeed the way to go but I am close to the city, so I would have to get them to ok it, pay for permits, etc before they will see fit to allow me to actually do anything......one day though...

Good idea on the lug nut swap to check bolt patterns. A lug from my original SBP front tires will indeed not fit on the studs of the existing back tires, so I guess I have BBP back wheels already so thats great news.

I plan on redoing the back disk brakes and like you said, maybe upgrade the rear end later if I do indeed have the 7-1/4".

Searching for rear end id chart I found this:

So with this pic and my 2.5"(?) tubes, looks like its a 7-1/4"? But see below about the u bolt width.

moparmat2000 said
You can also measure the width of the U bolts at the spring plates. If its under 3" you have a 7.25" and still thats not bad.

Looks like the u bolt width is over 3, so it could be a 8-1/4"?.....
hmm