Of the three everyone seems to have narrowed down, Kirkham, Shelby, and ERA, I prefer Kirkham. I work for them so I am not biased at all!
. Not only have they maintained originality in just about every way they have also improved things like suspension and brakes from the originals. Most have more power to not that you'd need it. We just shipped off a car yesterday with a fuel injected, dry sump, 427 SOHC motor which produces somewhere in the neighborhood of 700-800hp.