00 Freak

iTrader: (34)

Would I need the PCM and wire harness for a 408 swap. I tried the search and found everything else I needed but except this question I had. Thanks

DrkPhx

iTrader: (15)

You can use the stock PCM and harness for an iron block 408. All the original sensors will fit.

Beast96Z

iTrader: (21)

You use the wire harness that is in the car. No GM car/trucks come with 408's, so there is no harness/PCM to swap with. The motor/intake itself is not physically diffrent on the outside. Only the internals change. Therefore, all the parts from your motor swap over to the new 408, hence your wiring harness pugging back in. Once installed, you carry the car to a speed shop and have them dyno tune. Basically, your PCM needs to be reprogrammed while monitoring/tweaking the motor functions on the dyno.

00 Freak

iTrader: (34)

Sweet. Thanks a lot fellas.