78-81 rear end interchange into 87?

[daveSS1987]

Simple question. any difference in the 78-81 A-G body rear end to the ones in the 82-88 other than the standard wheel studs? Reason I'm asking is Master Power Brakes had an ad in the newest Chevy High performance advertising 11" rear drum brake kits that it says fit 64-81 midsize. they are 4 bolt backing plates, not 3 bolt like on my 87. Did all of the 78-81 rear ends have 4 bolt backing plates? Will the 7.5 posi in a 1987 bolt right in? may be a way to do easy disk brake conversions or larger drum conversions without the hard to fit 3 bolt backing plates on all of our later axles. Anyone that has an older axle let me know if they are definately 4 bolt backing plates but otherwise same dimensions as the newer ones.
thanks,
Dave

 

[85 Cutlass Brougham]

They are all 3 bolt flanges. I had a axle from a 78 that I pulled the posi from, and it had the 3 bolt flange. All 7.5 G body axles do. The thing is, brakes are not easy to find for these axles because they are weak, and anyone serious about building these cars usually swaps to something beefier. I have a 7.5 now, but I too plan on swapping to a 8.5 axle from a 442/turbo Regal instead as I fear breaking the weak 7.5 should I ever get traction.

 

[daveSS1987]

So the MP brakes must be a typo, they definately won't bolt up to a 78-81 midsize. (Unless they consider the Camaro a midsize, but I always thought the A/G body was the midsize. ) Well worth a try, thanks for the correct info.
dave