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OK, I need some validation.

Working on a car where the owner wants to convert from 6V to 12V. But it is a bigger issue than that. He dropped a Chevy 350 into the car.

I created 2 wire diagrams. The first one (entitled 48 Packard 6V)shows every wire that has anything to do with the '48 Packard engine.

The second one (entitled 48 Packard 12V Chevy 350)shows the '48 with the Chevy 350 wiring. I need to know if I show all of the wires correctly on the second one.

Please take a good look and either let me know if I have it right, or what (if anything) I missed or need to change.

So far I have been told to swap the wiring to the AMM Gauge + & -, which I did. My biggest concern are the wires from the Alternator & Distributor. Do I have these correct? Do I have everything else correct.

What a pain this has been, but learning a lot which is a good thing.

Thank you so much!

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I would question the alternator connections. Guess it depends on which one you use but I'll throw in a couple of my concerns or questions if you're using the common 10SI. There are others on the forum that can give better advice on alternator wiring.

This articleoldengine.org/unfaq/10si.htm says #1 terminal is for a light. If so, I don't think you want it connected directly to the splice since that #1 terminal will switch to ground according to the description.

Going directly to the battery with the alternator output will mean the ammeter is not going to give a true picture of the state of things and will most likely show a continual discharge. Don't know how much output your alternator will have but the stock ammeter capacity is probably a max of 35-40 amps. In this case I don't think there is much option so something to be aware of.

Think we've discussed the carb switch wiring which would relocate to the new pushbutton on the Chevy but otherwise would remain intact.

Ahhh yes, the push button. I need to get that into my diagram.

The alternator is a stock 1970s style that puts out I believe about 50A?

I understand your point about not wiring the #1 Alternator terminal to the splice. I read your link and it says to use this wire for a warning light or resistor. The '48 does not have a warning light, and I have no idea what/where a resister is for.

Attached is my updated 12V Small Block Wiring Diagram.

The changes are as follows:

1) I added a Start Button
2) Took the Alternator Terminal 1 wire out of the splice and directly wired it to a warning light.

So, I took liberty with the push button and wired it directly to the starter.

So this opens 2 more questions for me.

Regarding the Warning Light, if the owner does not want a warning light, what should I do with this wire? If he is OK with a warning light, where do I get one and how do you wire it up? Straight to ground? And what about this resistor I keep hearing about? Where does that go?

Second question deals with push button start. In the '48, when the gas pedal was depressed, the wiring circuit took voltage from the Ignition Switch (GA) thru the Ultramatic Transmission, then thru the Carburetor, then to the Starter. This is why I went straight from the Ignition Switch (GA) to the Starter. Is this correct?

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One more question. Wire # 66 on my diagram.

For 6V, it was connected to AMM (+). With 12V should it still got to + since it is going into the splice that feeds into the light switch, the fuse block and the ignition switch? Or do I connect it to (-) as shown?