iirc, most of the 71-76 Riviera ( RWD E-body, the Caddy Eldo and Olds Toro are FWD ) is compatible with the other GM Senior Model series ( B-body, C-body, D-body ) cars.
for instance, a small block LeSabre is the source for an 8 1/2" ring gear rear end that can be used in any of the other Senior series cars. so you can actually get any gear ration you want into a Riv or Electra.
you just have to swap the whole rear housing out. the benefit is that you can get a lot more parts for the small block Regal / LeSabre rear AND you're also spinning less rotating mass. the downside is that it's not as durable as a 9 3/8s rear.
The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
Government schooling is about "the perfect organization of the hive."
H.H. Goddard, Human Efficiency (1920)