Hyper Pak vs Super Six
If it were me, and cold weather drivability was on equal footing with performance, I would raise compression, mild cam, and keep super six with iron exhaust manifold, and warm air air cleaner. Probably best low cost option.
If horsepower was more important than sub-arctic good manners, I would use a bit more compression, performance cam, four barrel and headders. A performance oriented carb will tend to be jetted richer and a mechanical choke would make cold weather operation a bit better. Shouldn't be too much more expensive than a basically stock V-8.
Fuel injection?
If you havent already done so, take a look here also...
www.slantsix.org
Just a thought...