Check out Rockauto.com. You run into a few good guys in the parts stores (I worked at one for awhile!) , but more often then not, they just don't know.
Rockauto shows one without vacuum advance for an 89 Ramcharger from Cardone. Here's a link to Rockauto and Cardone.
1989 DODGE RAMCHARGER 5.2L 318cid V8 Distributor | RockAuto
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