Fuel Processor

[cocheese72]

I have a stock Nomad with the baffles drilled out. The other flat baffles deep in muffler were hit with a pipe and are kinda flattened in on the walls of the pipe but not totally out. Goat Belly intact. My question is, if I leave this intake alone, and the exhaust as is, and add a TFI or FI2000R to eliminate pinging, what should I expect the MPG to do. Would this go up possibly, or will it most definitely get worse? What if the intake and exhaust are opened?

I currently range around 37-39mpg. Would like to go into 42-45mpg, if anyway possible.