What rear in 73-74?

I’m not near my 1974 GS but was wondering what rear is in it so maybe I can upgrade and want to order parts. It’s a 350-4 with a non-posi 2:73 currently, Is it the same 8.5 that’s in 1972’s ?

 

Hi, the guts are the same however the housing has a different width and suspension mounting point brackets.

 

Cool…… so I can use the same posi and 3:42 out of any 8.5 then, making it an affordable, easy swap, and a huge upgrade on the Performance for sure.

 

Axles are different but the same spline count so yes you can use the gears and possi from the 71-72 rear ends.

 

those a bodies came with axle code b, g, k, and 2 others. had either pressed on bearings or the c-clip cheapo axle bearings that the race was the axle. those tended to wear a groove in the axle. bca sells extended bearings to move the wear groove. kind of hokey but it works. if you hear squeaks out of the rear, usually the cheapo bearings.
72 and earlier rear axle have the lower shock mount opposite the 73 >'s. when 12 bolt posi's were $25.00, i had the perches cut off the 10 bolt and welded on the 12 bolt. the oem lower control arms fit, but the uppers are 66's. the oem bushings in the lowers are junk. a 70 gs th400 driveshaft will work in a pinch. it needs to be about an inch shorter to be good. also the 12 bolt is narrower than the 10. with the wheel well as big as it is, this makes more rim offset selections for slick position. never used or needed traction bars when i racing the 73, it always hooked with tires or slicks. the 10 bolt gear ratios were up to 4.66's with the right chuck.. i used 4.56's in the 12 bolt.
thats all i remember

 

So starting with the factory 8.5 and Stock 2:73, when I replace with a aftermarket Posi unit I can go up to a 3:42 gear without any problems with that housing I assume?

 

You can install any gear ratio that you want into that housing. The posi unit is the same for 2:73 and numerically higher ratios.

 

Great to know Brian thanks! V8 comes thru again!

 

That is great looking 1974 Gran Sport ,post some more pics?

 

I have found Sport steering wheel and Floor mats to that will compliment it more soon.