Instrument Cluster Changeover?

[Richard Dobson]

I am going to swap out a idiot light instrument cluster for a fully instrumented (except for vacuum gage) instrument cluster . The board guys advised me to check out GMC Pauls site which describes in detail what to do.
But what are the GMC Pauls diagrams of, "the bulk head under the hood" or "The fuse panel"? Would you advise me to buy a new wiring harness since I have a HEI ignition or use this as a guide to save money. Thanks
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