Andy,
If you want to go to a disc brake conversion, there are several options available. I have personally used kits from Charlie at www.rustyhope.com. All the available kits require some work, but there is one out there that is suppose to use off the shelf parts that you don't have to modify anything on your car to do, unfortunately, I don't have a link to it.

Don't let the motorheads lead you astray, the flathead 6 in a modified form, like yours, is fully capable of keeping up with traffic. I wouldn't want to do much drag racing, but they make great drivers. Gene