Glad the 8.1 was short lived. I've only worked on one 3/4 ton Avalanche that had the 8.1 and, it's nothing special. It was a last ditch effort to keep the big block around and it was a major gas drinker. The 7.4/454 at least could be made for serious power, going off the newer (post 1970s) standard. To be fair, all those engines, before the standard change over, made the same amount of power, technically. In the old standard, auto makers would use race spec parts, open headers, etc to market insane numbers. Not many young ones know this.