Hi all, I intend to use the adjustable VR that Chrysler used in police and heavy duty applications back in the 60s - I have two NOS ones. The adjustability comes in the form of idle speed alternator output - you can bump it up a little to reduce or eliminate the traditional brownout our cars demonstrate when at idle in gear with lights/AC/radio on etc. This particular VR is what my Monaco came with due to the police engine package that it received - the factory used a special mounting bracket on the inner fender for cooling, as opposed to mounting it on the firewall as they typically did. You can see the VR on my inner fender on it's bracket, just in front of the booster. My concern is this: I will be using either Pertronix OR the Mopar Performance electronic ignition system (with a generic box rather than the failure-prone orange box) and it's my understanding that electronic ignition systems don't like mechanical VRs and vice versa. In the past I've used one of the electronic VRs in a vintage case (from Bill Corcoran) with no problems, but they still brown out at idle just like the mechanical standard ones. What can/should I do to be able to use both my electronic ignition and the vintage adjustable mechanical VR? They are kind of expensive, and I don't want to burn them up... lol. I wouldn't be opposed to peeling the case off one to have a look as long as I felt I'd be able to not mark it up... For what it's worth, I am using a single wire original style round-back alternator. I've already had a response from @Mike66Chryslers in a PM, and this is what his thoughts are: Interesting question. I presume that the main problem is the opening and closing of the contacts in the Vreg puts high-frequency noise on the power rail. If the ignition ECU doesn't have sufficient noise filtering, this noise will go right into the ECU electronics. The ECU power is usually wired to the same ignition-switched circuit as the Vreg, so there wouldn't be much else like a long wire run to dampen the noise. Ideally I would like to put an oscilloscope on the IGN terminal of the Vreg to see what noise the Vreg is injecting onto it, then design a filter to block those frequencies at the source. You may be OK just putting a condenser from a distributor between IGN and ground, and one of those snap-on ferrite chokes with the IGN wire wrapped around it a couple times, to make an LC filter. The noise could also be getting onto the power rail from the FLD output and through the alternator. Certainly the switching noise is getting onto the Vreg FLD output, but I think it's a lot less likely that it gets through to the alternator BAT terminal though. I am interested in what people have to say and their experience of similar situations. Thanks all!