honest question because I dont know, but why go with a belt at all. Wouldnt it just be better to run a driveshaft? Sure it might have added a bit of weight, but were they even trying to keep the weight down in these monsters?
I suspect that in the beginning going down the "belt drive" route seemed to offer low development costs, low manufacturing cost and great relaibility.
With 20/20 hind sight perhaps they were a bit over optimistic.
