Help on Wiring case SC 1952

Get a plug with short pigtails for the 2 pin edge connector

Loop #2 down to output stud, output stud to ammeter

Connect #1 through your oil pressure switch to output (coil) side of ignition switch

Alternator should ground through the mount so get a good clean contact there and you shouldn't need the extra ground wire

Install battery negative to ground

Put the coil back on and don't worry about it. - post to distributor and + post to on/off switch output

Yes, you definitely need a regulator for the alternator. No you do not need a resistor for the coil.

If it were mine, rather than investing in a regulator I would change it to a Delco internal regulated alternator from early 80's GM vehicle, or a smaller case Hitachi from a late 70's - early 80's Datsun/Nissan. They both wire up the same. Choice might depend on mounting room

The "regulating" was done manually through a resistor on the light switch. Not used with and alternator

Hopefully you have the regulator for that alternator? It will not work without it.

You have done a very good job with the pictures. They are a big help.

What brand alternator are you using? Doesn't look like the commonly used Delco. Is it a one wire configuration? Alternator case should ground through the mount, so do alternator instructions call for an extra ground wire?

One possibility for the oil pressure switch is that it was used to turn on a previous Delco 3 wire alternator. One side of pressure switch to switched side of on/off switch, and other side of pressure switch to #1 pin of 2 pin plug on alternator. Makes no difference which way the pressure switch is connected.

With out some form of isolation (switch, indicator light, resistor, or diode) there may be feed back from #1 pin of alternator to output of ignition switch to coil that will cause the engine to continue to run when the ignition switch is turned off.

Your alternator should be negative ground and -- post on coil should go to distributor.

A coil with 1 1/2 ohms between + and - can be labeled either 6 volt or "12 volts external resistor required". For 12 volt system it requires an external resistor with resistance approximately equal to resistance of the coil. This is to limit current and prevent burning of points and overheating the coil.

With points open, either coil should read near battery voltage at input side and output to side of the distributor.

With points closed a Direct 12 volt coil (3 ohm) should read near battery voltage at input and near zero volts at coil to side distributor wire.

With points closed, a 1 1/2 ohm coil with resistor in 12 volt system should read near battery at input to the resistor, approximately half battery voltage at input to the coil, and near zero volts between output of coil and side of distributor.

In reality, there is no separate resistor inside of a 3 ohm coil. The coil is a transformer with one side of primary and one side of secondary (high voltage side) tied together. The primary resistance is determined by the type of wire and number of turns used.

Coil in the picture appears to me to be blue with gray over spray. I'd not be surprised if it is a 3 ohm direct 12 volt coil.