wiring harness should it go?

[Musclerodz]

If your connectors are good, I would lean towards the Highway 22 kit since AAW does not have a vehicle specific kit for the 68-72 Chevelle yet. You would have to plug your original box hole, but the Hwy 22 gives you the ability to only install what wires you need and leave out what you don't. It has terminal connections to power to your efi harness, plus any other aftermarket option you might want to add with piggybacking into the system. I have installed several and very happy with how easy they are to install and follow instructions.

Also, having Speartech do your harness should be a no brainer.