5.7 Hemi into an old Suburban.

Gotta admire the guy that takes the opportunity to build a sbc for 1/5 the cost of any mopar engine, and then picks one of the more complicated swaps of the mopar world. Lol

If you have a complete pcm and harness, there is no reason to look elsewhere beyond that. Plenty of companies that adjust the factory pcm to work for swaps. Plus you can use the oem cluster. Also cheaper than after market.

We use the holley swap ecm and harness, with aftermarket gauges on ours...but we start with new long blocks, and there isnt a point to us buying oem harness/pcm, just to get gouged on price, then send it back out to be modified. Hence the use of the holley. But again we dont do any used ones...so thats a different animal.