Hei conversion troubleshooting

pishta said
Squareback alternators using an older mechanical VR with 1 field output must have one of the alternator fields grounded to the case/body/batt - however you want to wire it. The other will go to the points style VR. True electro-mechanical 68ish VR's will have 2 rods exposed on the back. If its flat with 2 straps, it an electronic retrofit.
"...You can use a dual field alternator in an single field (pre 1970) car by using a jumper on one field to ground, but you can't use a single field alternator on a dual field (1970 and up) car..."

The back of my VR has some ballast-resistor lookin coils running diagonally across it. So I'm assuming its the old-style. Looks pretty though, no corrosion looks brand new.

I'm a little confused on the alternator ID. My car is a '67. It is obviously not the original alternator. It has 2 FLD terminals, So it is a dual field, and I need to ground one of the fields? Which one, does it matter? The one that is not hooked up has an insultor around the terminal, not sure what for.