At 278K, the 350 in my '91 Blazer is way too week. I have the idea to install the TBI454 from my '87 GMC 3500 in it. This is were most of ya are gonna kill me...I want to keep it stock apearing! This truck is completely original except 6" suspension lift...never seen a winter...even original paint! I use it as a summer toy and would like to be able to tow our small travel trailer. I would wheel it if I knew I could be capable w/o having to thrash the truck...at some point I will be there...just not with stock/open drivetrain. I know the AC unit is mounted on the other side so I have a post in the WANTED section for those parts. Did the '91 BB trucks have the same cast iron intake with adaptor for TBI unit as in my '87 donor? Same "blue" engine/stamped valve covers? Will my new 4L60 (700R4) hold up to street use behind stock 454? What about towing 5000lbs? What about 241 t-case? I am already looking for a 6-lug 14 bolt so I can use my tires/wheels. In the future, I plan to swap in D60 and FF 14bolt from the donor...just too expensive to go through them and buy tires/wheels at this point. Will 350 cooling system work? Will vacuume booster/brakes be adequate or should I swap in Hydroboost? What about my stock ABS (RWAL)? Anything else I should think of?