Lean-Burn Dual P/U Distributors - Any Good?

Thanks everyone for all the great ideas. Rapid Robert might have put the final nail in this idea for now. I've never seen one of these units in the flesh and didn't know the timing was locked out on them. The Mallory 685 is smarter then the average box but doesn't have the juice to provide complete timing control. FI will be way down the road for me. I've spotted a batch of Mallory Dual Sync distributors on that auction site for $100. These seem too cheap to be true. I'm a little leary of Mallory at this point since they're a dead issue and replacement parts thru MSD are so expensive. For now I'm leaning towards of putting a nice curve in a stock single pick-up magnetic distributor and run it with a 685 box with an E-core coil. I'll pick up a simular distributor, have it curved, and convert it to run a GM HEI module. I'll leave this unit wrapped up in a spare-parts box in the trunk in case the 685 box goes out. I've been tempted to get one of the off-shore billet distributors that are so comonn now but whenever I asked about replacement parts beyond a cap & rotor nobody will return a message.