I purchased my wife a 1998 z28 roller, currently I have purchased a 0411 99 pcm and sending the wiring harness out to get modified, for the 4l80e swap and 99 pcm...I have jumped power to check radio,and power windows...can someone tell me which wire I can jump to check miles on,chassis.?

I really wish I had removed the motor this is gonna be tough first LS and an empty engine compartment I have zero knowledge of

Thanks?