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Old 04-09-2024, 07:37 PM
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RocktimusPryme RocktimusPryme is offline
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Default Best vacuum advance distributor to trigger MSD box.

This is a bit of a compound question.

1. Would you still bother with vacuum advance on a high-effort street engine?
(Specifically, I'm putting together a drag week project)

Im generally inclined to say even if it veers on the "strip" side of a street/strip car that the vacuum advance is still going to make the engine happier and cooler on the road trip portions of a drag n drive event.

I want to use an ignition box. 80% because of the Rev Limiter (Possibly even a 2 step) and 20% because of performance advantages of a CDI ignition. I just don't want to annihilate an expensive engine by unloading it if you lose a $40 U-joint.

So Question 2.

2. What is the best type of distributor to trigger with a CDI box that still has vacuum advance for cruise?

Probably needs to be small cap, I tentatively have my eyes on tunnel ram, so a big cap HEI might be a problem.

Bascially for every engine family under the sun there is a "Billet" option that is just a mechanical advance 2 wire distributor. Then there is a "Ready to Run" which looks the same but has three wires and doesn't need an ignition box. Both made by MSD and in house brands like Jegs and Summit.

Then there big cap HEIs and small Cap Pertronix II and IIIs available but I think those might be hall effect and the CDI boxes want a magnetic pickup. One of the Pertronix distributors actually has a built in Rev Limiter.

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