Right, but I was just wondering why my Challenger with a lowly ol' 318 2 barrel came with the beefy 8 3/4" rear while my firend's 72 Charger (with a lot more engine) didn't. Was it just more economical to use one rear end (the 8 3/4") for all the later E - bodies since there were not as many made? For that matter, wouldn't it have been easier to just make one style of rear end housing and modify it for the body it would be used for?