Cabbie Caprice

Hi there, i have a 91 Caprice with a 305 in it that i bought a couple of months back, but i have a problem, it runs on propane and not gas(the hassle of finding pumps that have the gas). Now, I have another Chevy caprice that i will use for parts (its complete) but i don't know what i'll need to modify other than putting a gas tank, fuel pump, throttle body, injectors, ECM and a gas intake in it. This is the first vehicle i bought with propane power, but i bought it for $300, and it's got a better body than my original Capo. It's got 11" rear drums, 9" rear end and 3.42 gears. I really need some advice because I have no idea where to start.
Thanks,
Val