Hi, I am trying to get and idea of about how much it should cost me to have a mechanic replace the 454 engine in my 1994 K2500 Suburban. I would like information on replacing it with a Jasper or similar remanufactured engine with a good warranty. Any recommendations or advice? Also, what should I typically get for gas mileage? I know...it's not an economy car. Also, what are the most basic few things I can do to my new engine to get an increase in performance. I will be towing about 7K camper. Thanks for helping me out.