You only have to look at last years Hot Rod Magazine's Drag Week results to see what a turbo can do. Joh Huber's 4 cylinder Mustang was faster that the small blocks with power adders and the big blocks with power adders. Only one car was faster and it was running in the unlimited category.
What BadgeZ28 said. I think it was last year, but Hot Rod ran an article on a little Pontiac tempest with 2 turbos back around the rearend and plumbed the boosted air back to the front through the firewall. Pretty well hidden! He was launching the wheels every run!
It may be difficult (impossible?) to package all the needed electronic gizmos and and intercooler well enough to keep a car looking traditional especially in a 1930's car. But anybody who doesn't beleive that a turbo system properly setup can produce absolutely massive power is fooling themselves.