head lights pulse after bypassing my bulkhead

74 should be electronic

You might have somehow created a "loop" that is causing an oscillation

Start by wiggling the #### out of the VR connector several times to scrub the terminals clean

Clean the firewall and mounting ears on the VR and remount tight with star lock washers

CHECK for voltage drop both the ground and harness sections

To do this, Hook one probe of your meter to the "I" buss, IE switched ignition. One place you can access it is the blue field wire on the alternator. If you still have a ballast resistor, the "key" side of it

Hook the remaining probe to battery POSitive.

With the meter set on low DC volts, and the key in "run" but engine stopped, you are hoping for a very low reading, less than .3V. That's 3 tenths of one volt. You want to measure this with everything hooked up "normal."

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Ground side. Make this test with battery running at fast idle, warm, and battery "normalized." Check first with all accessories off, again with lights, heater, etc, on

Stab one probe right into the top of the NEGative battery stud. Stab the other into the mounting flange of the VR. Be sure to stab through any chrome, paint, rust. Again you are hoping for a low reading, not over .2V and zero volts would be perfect

If you google stuff like "ground loops" this might be what you've set up here, if it's not a "drop" problem. You can have a situation where you start an oscillation. These can be difficult to diagnose. One example of this is feedback in a PA system.
You are on a podium, with a PA. The mike picks up some noise, the amplifier makes it loud, and the speaker reproduces the noise......louder. The mike picks this noise up louder this time right from the speaker, and "sends it around again." Because of the time constants of the circuitry in the system, this turns into a howl

Because the time constant of the alternator / VR circuits is very slow, you have a pulsing.