How hard would it be to swap the 4.3 out of my 2003 Silverado for a 4.8 or 5.3 v8 engine. I plan on finding an engine out of the same year model truck or newer. I know i need the motor mounts and the fuel pump but what else do i need such as hoses, wiring, ac stuff etc. and would i need to get a computer from nelson performance and have mine reflashed ur information would be greatly needed and about how much will all this cost