Don, I have only ever seen the 3:31 open (CRU), 3:31 posi (CRV) and 4:10 posi (CRW) in these cars and that is after researching literally hundreds of cars. Not to say that it could not happen but I seriously doubt it. All three of the above rearends were designated 454 rear ends and I know of no special 454 designated 3:08 rear codes nor can I imagine why GM would put an "economy" rear behind a solid lifter 450 hp engine in the first place.
