Help identifying differential 65 Barracuda V8

coast2coastkidd85 said

I appreciate that perspective, thank you, and that’s exactly why I asked… I’m taking everything into consideration, im at a crossroads with deciding the future of the differential with the future upgrades in mind…

in exploring the two 8 diffs you mentioned, is there an adapter or anything that could be done to still allow me to run my dads wheels that were on the 7-1/4”? Not to be petty but they are sentimental to him and the story of the car but obviously not a priority over mechanical reliability…

I suppose this also changes my rear brake lines and brake needs… currently 10” drums all around and was just about to order a full replacement brake line kit soon… will this get me in trouble with the driveshaft as well? Will the 904 be able to handle all of this? thanks for the feedback!

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The 904 can handle anything you’re going to throw at it. Now, the 7 1/4” and 8 3/4” use the same size brakes, 1 3/4” wide shoes and a 10” diameter. The line set for the axle itself would be different, but you may not need that anyway. The drums will be the same, and all the hardware. The backing plates would swap over to an 8 3/4” from your axle, but a 7 1/4” backing plate is held on with 4 studs, the 8 3/4” has 5. You would just need to drill the 5th hole. All A body 8 3/4” axles came with the small bolt pattern, so unless the axles have been changed to an aftermarket axle with the large bolt pattern, you can use your existing rims. The driveshaft would have to be shortened with either axle I mentioned in my previous post.

If you just want to use the 7 1/4”, there are literally hundreds of them available that were removed for a differential upgrade, and they would be cheap, or most times free. You can surely find one that is in good condition that you could put right in place, but the fact remains that they are undersized for any spirited driving.