Deflep

Hey does anybody know what you do with the positive lead from the battery cable that was hooked to the fuse box/center, to power it. I now have a stand alone harness. 5.3 vortec from 03 Tahoe Z vin, it's in a 71 Chevy Cheyenne. To recap, I have the red positive cable from battery, thicker cable going to starter and the smaller one going nowhere now I don't have the fuse center. Do I hook it to the junction block that originally was in line from firewall fuse block harness over to the positive battery cable?