I installed his system a couple of years ago in my '57. The directions were less than helpful.
It sounds like the harness may have been assembled incorrectly (imagine that) and b1 (10ga brown wire - power out from the ignition switch to the switched side of the fuse block) and b2 (12ga red wire - power into the switch from the fuse block) may have been reversed in the connector.
Run a continuity check on the column connector to isolate the "ACC" (switched) output. (It should be dead when the switch is off and hot when the switch is on or in the acc position. If it's always hot you've got a bad switch.) This should mate up to the brown (b1 10ga wire) on the new harness which provides power to the fuses (a1-a6/d1-d6 on my diagram). The red 12ga wire (b2) provides power into the ign switch and is always hot. Then run a continuity check from the harness connector at the ign switch end (b1) to one of the fuses (a1-a6 or d1-d6) to see if that's connected to the block in the switched half. If it shows continuity to the "hot" half of the fuse block (a7-a10/d7-d10) then the brown wire (b1) at the fuse block is coming from the wrong half of the fuse block.
Also make sure your 8ga wire (also b2 on the diagram) is the wire that goes directly from the fuse block to the battery.
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