part 2...
I've Always preferred Danas. Hemi's 440's 413's etc, never once a rear end failure with a Ford 9 or a Dana 60. 8-/34'swere very stout, too, but I did break two of them over the years. one shattered the ring gear, and the other sheared the splines off one of the axles. The switch t Ford 9's and Dana's and the problem went away.
I found that using quality aftermarket components in the 8-3/4 rears worked great, but it was too expensive. I could get a 9" and even a 60 for less than the cost of a built 8-3/4, and the 9" had a far greater gear ratio selection available for them than just about anything else on the market at the time, including the GM 12 Bolt.
Also, the V8 Options in 1976 were 318, 360, 400, 440. On the 200 and 300 all V8's came with 727's. The 225 slant 6 was available in the 100,200,300's but I believe they used 904/999 transmissions.