91 454 rebuild and questions

[91 Rust Bucket]

Hello, I'm new here but not new to engine building. I have a few questions. I have a 91 GMC 2500 Sub 2wd, the engine has 251k and counting. It gets terrible fuel mileage, but it pulls my trailer with ease most of the time.. The engine seems a little tired and possibly in need of refreshing. Now I am wanting to know what would it take to convert from the TBI over to a 4 barrel car, I know that swapping the intakes are about universal. But, my main concern is the computer issues. Would I be ok with the stock ignition setup once the rebuild has been completed? I have the intake and an 800 cfm Q-Jet that has been tweaked for the engine. Or would it be best to bypass the newer style ignition system and switch over to an HEI style distributor? Would I need to swap a wire harness from an older truck or could I get away bypassing the computer? I know the truck has the big tranny in it, not the 700R4. Tranny was rebuilt about a year ago!Any opinions are welcome. I have the parts and the means to do everything needed. I also want to know what lift cam would be in this engine in stock form? I am considering a decent RV cam of some type. I am actually diesel Ford truck guy asking questions about this. I had inherited the truck and I started liking it! Or does anyone know if an Olds 455 will bolt up to the existing transmission with an adapter of some sort? I have a 650 horse 455 that I built for an older motor home.

Thanks Paul