AD Gonzalez-Harding

Hey guys! first time posting, been lurking for about 5-6 years now. recently picked up a 1999 Z28, with a rod knock. decided to pull the motor, and swap in a low miles 5.3, anyways I bolted it all back together and such, and now I have a crank but no start condition, and the whole instrument cluster is going nuts, no info is showing up on the small screen for the odometer, and all the gauges are going all over the place. any ideas where to start?? thanks in advance!