I have never seen one, ever, in a 454 3/4 or any 3/4 ton Suburban. I have owned 3 Suburbans and my latest, a 89 3/4 ton came with a 14bsf.
77 and older Suburban's probably did have a 14b ff. What does 88-98 Suburbans mean? Old body style ended in 91 and have nothing in common with 92 and newer. 14b ff from 89 on are different as well, they have metric threads and some other differences.
Not trying to start an arguement, but I, as well as quite a few people here have never seen a Suburban with a 14bff that wasnt transplanted from another truck.