Switching rear end to lbp

[jim ayers]

Hi,

I am a MOPAR newbie and I am sure this question has been answered before,
but i have a stock 69 barracuda with 4 wheel drums and 8.75 rear. I have an opportunity to strip a disk brake setup from a 73 340 duster. Since this setup will have 4.5 inch bolt circle (and assuming rotors are useable), can I just yank the axles out of the rear of the donor car and use them in my 69 rear end so that I am LBP all the way around? Also, if rotors are trash, will 72 and earlier rotor fit on the spindle so that I can maintain the SBP all the way around?

thanks

 

[crackedback]

Rotors don't swap from 72 earlier to the 73+ spindles.

The rear in that duster is likely a 8.25 and the axles will not work in a 8.75. Grab the drums, backing plates, e brake cables off the 8.25 if it's there and use those if you buy BBP aftermarket axles.

 

[twofosho]

Mopar was famous for using the same combi valve for everything and as a result virtually every stock disc brake A body would/will spin like a top with seriously aggressive brake application, even on dry pavement. Replacing the stock disc/drum setup rear wheel cylinders with smaller diameter ones, gutting the proportioning valve section of the OEM combi valve and using an aftermarket adjustable, not to mention taking the time to properly adjust it, is something well worth doing. It might make your life a little less exciting in a panic brake situation, but could be considered as taking a little step toward self and car preservation.

Also, A body 73-75 front caliper is 2.60 inch diameter. 76 and newer disc use a caliper with a larger bore, 2.75 inch, same as late 70's B body. Some or most later B and R bodies also have a larger rotor that bolts to the A body spindle after finding a set of the correct large rotor caliper brackets for the type of caliper (slider or pin) you have, and makes for an easy bolt on upgrade. While your at it, find a pair of the stronger reinforced replacement (think cop car) larger diameter rotors. Taken from one of their magazine articles of a dozen or so years ago, the Mopar Action website has an entire section with pics detailing what you need to know.

Once you you get up to speed on the basics we can start talking about F M J spindles, B body lower control arms, adjustable strut rods, and the various big diameter aluminum caliper Cobra and Viper conversions (AR Engineering), both front and rear.

 

[805moparkid]

Rotors don't swap from 72 earlier to the 73+ spindles.

The rear in that duster is likely a 8.25 and the axles will not work in a 8.75. Grab the drums, backing plates, e brake cables off the 8.25 if it's there and use those if you buy BBP aftermarket axles.

my new axles from doctordiff should be here tomarrow so i can post pics