Yep all the wiring will plug right in.. there is enough "extra" built into the wiring harness to span the relatively small dimensional differences between these motors. There are a few hard parts that are unique to the 5.8 so you are well advised to start with a complete 5.8EFI motor, the distributor, flexplate and balancer, exhaust manifolds, and the air injection crossover tube at the back of the heads are all different and take into account the wider deck, different primary imbalance(28oz vs 50oz), and different routing of the EGR system.. into the pass side exhaust manifold instead of into the lower intake manifold. Both motors use the same throttlebody though so no issue attaching the intake plumbing. I have had both motors in my truck and changed nothing except the exhaust Y pipe which has to be widened slightly for the 5.8.