The actual reason it died was easy: the Toronados powertrain was being downgraded for 1979. It wasn't practical for GM to keep the older powertrain just for the motorhome, and as many people were buying trucks, well there you go.
As for my 78 model, it's getting modern EFI, and a 500 CI Cadillac. It's the hot rod with plumbing.
We also have modern 1 ton frontend and all wheel disc brakes and revised air suspension for them. The GMC moths a support industry much as the fiero does.
[This message has been edited by htexans1 (edited 11-26-2018).]