89 4.0L to 91+ HO 4.0L

I have a 89 4.0L with almost 250K and have been thinking of updating to an HO 4.0L. I have access to a 93 motor and ECM. Will I have to change the ECM and will it plug into my wiring harness? Some have suggested putting my intake and exhaust manifolds on it and keep my ECM. I'm lookng for a few more ponys. Or maybe jest install a 2003 GM vortec V8 crate motor.

You can just drill and tap the HO block for the knock sensor and use the complete engine and adapt your tps to work with the HO. swapping wiring harnesses would be a major pain in the ass. I would take a renix rig over an HO rig any day. A V-8 swap is not as easy as it sounds that's why I ended up stroking my motor.

The only reason I mention the computer is to get the right mapping. After looking at some of the other posts on the subject it looks like the cams the same. the rewire doesn't bother me...put factory AC in and reprogrammed the computer once. That said, I'll keep the stock harness and computer.

i just put a 93 ho in my 88 with renix a few months ago. i put my intake and exhast manifold on it, it already had the place for the knock sensor, just had a plug in it. my ho came out of a grand cherokee, and had a diff waterpump, so put the old one on it along with all the accesorrys and oil pan. not a hard swap at all.

kolby