MSA tells me you can't get a vacuum pot for a '78 L28 dizzy (Auto trans/Fed spec.) so I need to find a compatible one.

Any suggestions?

Would there be a disadvantage to going with just the mechanical (9 deg) advance? It seems the vac pot can potentially add another 15 or so degrees of advance ...

thx.

Have you tried your local Nissan dealer? Just 2 months ago I ordered a vacuum advance unit for a '79 distributor from my local dealer and received it in about a week. Perhaps MSA gave the correct answer but a phone call to your dealer might be worth a try to double check. My unit was relatively expensive - about $75.

I don't recall how much advance is provided by the vacuum unit, but the disadvantage of not running the vacuum is some amount gas mileage reduction at part-throttle cruise.

The one I ordered from MSA was coming from the Canadian Nissan parts network, so I would have to assume the U.S. parts network has the same lack of stock on that. That's why I will probably have to settle for a used one, or something close to my oem unit. I would assume the advance curve on the vac pot might be a little different than my oem one.

thx