Cooking fuses

Ok, bear with me , this is a bit of a story. I will try to be concise.
1) Bought my 68 cuda, under dash wiring was a spaghetti bowl, found an uncut harness at Wildcat Auto wrecking.
2)No gauges worked so I went aftermarket and installed Mechanical oil pressure, tach, voltmeter, Water temp and fuel gauge.
3) I installed the O.P. gauge in the unused center hole of dash and the tach in what should have been ( I guess) a clock? The remaining 3 gauges hung under dash.
4) Did the Mad electrical bypass
5)Removed from the harness what seemed irrelevant, like wiring for factory gauges, heater (no heater in car), etc.
I was very careful when I did all this, didn't rush myself, felt I was thinking it all through before I made any move.
BUT I am worried that I awoke some demon of strange Mopar wiring oddities, because now the 20amp third fuse ( starting with INST/LAMPS) just keeps blowing. My diagram shows this to be Battery Feed, and my test light shows it to be always hot. Should that always be hot or is it regulated some way?
Neal Z.