JR , remember though, the 4.1 had the better crank and rods, same as turbo 3.8. The LeSabres came with the 3.8 also and in 78/79 ( Ithink) there was a turbo LeSabre sport coupe. Then I believe the Buick 350 was still also available. In fact I think maybe 79 FWD Riviera/Toro could be had with the 350 Olds or Buick I dont know. Im was never very pleased with the styling change that came about between 77 & 79 and still dont care much for anything from that era so I dont know much only what I came across researching the 3.8.
Fuddy - Here is the story of the Toronados drive system. Its alot of reading but very interesting at least to me because I am a GEN 1 Toro freak. Anyhow the aToro is Adam to our cars. Not the first FWD but the one that went into production and stayed up until all went transverse FWD in the 80'*. It where the prestreched drive chain was developed.
Just so no one gets confused
Toro was FWD from 66 until Aurora
Eldorado was FWD from 67 until discontinued
Riviera was RWD from 63 to 78, FWD from 79 until discontinued.