258 Distributor question.

258 Distributor question.

CJ7 Shadow

Woodbridge, VA
1985 CJ-7 4.2L T-5 Twin sticked D300 D30 AMC20 Weber Carb, Nutter Bypass, Emission parts & vacuum hose removal with the exception of EGR & Charcoal Canister, TFI ignition upgrade with Ford E-Core coil & 4.0L YJ plug wires (they are shorter than the 4.9L Ford wires)
The previous owner of my Jeep did the Nutter bypass and Weber carb. I did the rest.

I read somewhere that the computer controlled 258's did not have mechanical advance distributors. Is this true? If so, how do I know if mine's been changed?

Thanks in advance for any info y'all can provide.
The weights are below the rotor, they have the small springs attached at the ends.
Mine was computer controlled and I thoought it still had the weights in it
I guess I could hookup a timing light and disconnect the vacuum advance and see if I get any advance.

Sent from my DROIDX
If you have vacuum then its mechanical. Why would electronic need a vacuum hose?
If you have vacuum then its mechanical. Why would electronic need a vacuum hose?
I agree. I havent seen a stock 4.2 dizzy that didnt have vacuum advance (small vacuum line from carb to dizzy) :confused:
I think the only change was in how the computer controlled the vacuum advance....I cant find a mechanical difference in dizzys from 78-90. They may have used different springs, but they are essentially the same.

Distributor, Cap And Rotor, Remanufactured 83506286RK

The only search that came up to support the "junkyard genius'" webpage showed a different dizzy for an 84-90 Grand Wagoneer...everything else showed the CJ 4.2 dizzy as being the same from 1978 to 1990. Pre 1978 was a Prestolight ignition system.

The 4.2 I used in my CJ was from an '87 YJ and the dizzy was mechanical.

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