Yup, use a relay triggered by the coil + wire. That's what I did with the HEI that I had years ago, and still do for various electronic add-ons that need 12v while cranking. It also takes a good bit of load off of the dash harness.
One thing to note, you need to diode protect the excite circuit for your dash GEN light, otherwise power will back feed to the alternator and the engine won't shut down on key off.
If you're running a 1 wire alternator and don't have a functioning excite trigger and not using the dash light, there's no need to diode protect.
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-Jason
1969 Pontiac Firebird
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