So is the 426 the horsepower output and not the cubic inch displacement and that is why it's often referred to as a 426?
As far as looking for a car goes...I googled "1930's hot rods for sale" and came up with a bunch of sites....I'm sure I don't have to tell you that caution is always the answer when buying a car of this nature. If your going to spend that amount of money it's worth your while to physically look at the vehicle and if your not sure, maybe bring someone with you that knows cars, mechanically and with respect to the condition and work on the body. I know of a fellow locally that bought a car from many miles away, flew down and looked at it, bought it and a year later I had to rebuild the body and interior for him.
There may be other people on the site that know of 100% reputable Hot Rod sale places that can help you. The only one that comes to mind for me right now is Barrett Jackson Auctions. I try and get out there as often as I can and have always enjoyed the variety and in most cases the quality.
Just keep in mind that generally the faster it goes, the more it costs to keep it up.
Hope this helps