I've used Mallory Dual point distibutors on my four cylinder race car for the past couple years. I've had mixed results wuth the points setups on these. It is my belief that Mallory is no longer actively supporting points type distributors, even though they still produce them.
I recently (OK, it was last March) I had a set of points loose one of the contact pads. When questioned, Mallory responded with 'switch to unilite' and your problem will disappear.' After I spend $250 for a distributor, I'm not going to spend another $150 with Mallory because they don't appear to care about the quality of the points sets they make anymore. In addition, they want (IIRC) about $12 for a set of points and another $6 for a condenser making these parts alone a $30 tune up. Cap and rotor appear to remain reasonable priced.
All this being said, I'm still using the distributors, but I run Pertronix Ignitor II's in them. This is because I believe the distributor itself is robust, and they're actually not alot more expensive than a good rebuild on the old worn out 30 year old stock distributors I can get.
Since you probably don't need the additional dwell time on a six that the dual point offers, a well good stock distributor (with good bearings and minimum shaft endplay) with a good electronic trigger will probably serve you as well as a mallort dual point. If you need to run no vacuum advance, that feature can be removed from the distributor.
There are lots of ways to skin this cat- I personally think the Mallory dual point is a very expensive knife. and has alot more blades than required. That said, they're also a real pretty distrubutor with the machined aluminum body and all. The choice is yours, but the dual point alone will not buy you a performace improvment over a well tuned stock distrubutor until you start turning some serious RPM. And if your needing to ask the question you're asking, your probably not ready to build that kind of motor... yet