I've got an electronic breaker-less distributor from a 318 Aspen or Volare but it has no vacuum advance.... and am getting ready to drop in my rebuilt 1990 roller cam 318 LA motor in my 78 truck, running a Holley 650 and a Edelbrock performer rpm will this distributor work or should I go with a different one with the vacuum advance?

Sounds like a LeanBurn distributor.
This will be the weak link in any upgrade you attempt.
Get an electronic system upgrade and when you have your pieces all sorted out, send the distributor out to get custom curved.

You need both vacuum & mechanical advance for your application.

Thats definately a lean burn distributor you got there. A stock 78 truck should have electronic ignition right, not lean burn? Do you have a ECU box somehwere?

Will the distributor from a 94 Dakota with a 318 magnum work in my LA motor?

Nope, but since you got the wiring already for electronic go to the parts store and ask for a replacement distributor for a 1973 Dodge Challenger with a 360 and you'll be good to go. Last time I got one they were about $60 and the one I got worked great! They're rebuilt factory pieces. They didnt require a core either but if they did give them that lean burn one.

Autozone link

Looks like they want a core. Give them that LB one.

As said it's a LB one and not only has no vac adv but has no mechanical curve & it would have overheated your eng in minutes. Actually a junkyard unit (any SB one w a vac can) would work for you as eventually you'll be going inside it to adj the springs/slots and there's very little wear as there's no side thrust on the shaft/bushings like the old points ones so depending on time/access compared to your parts house price it might be a easier/cheaper deal to hit a JY. If your parts house has dist specs on the ones they sell get one w the least amt of mechanical adv (slot length) no matter what year SB it is listed for just as long as it has mech adv (springs/weights)