The Mopar Slant Six is one of the undisputed marvels of the engineering world; when the Sun goes supernova and the entire planet has been reduced to ionized hydrogen, a '67 Valiant will still be chugging along in the debris field (I once saw a Slant Six that had been completely filled with water- due to the owner's confusion about which cap to remove in order to add coolant- and had driven that way for weeks; the unpleasant noises and brown foam spewing out the tailpipe were apparently not regarded as meaningful). So it goes without saying that you can turbocharge the living hell out of one with no ill effects. Here's a nice article by a guy who put together a blown Dart for $400 with all-junkyard parts and a fair helping of ingenuity; sure, he's only running low 16s now, but that's probably about four seconds better than stock.
$400 Slant Six Turbo Setup [Slantsix.org]
Related:
If Slant 6 Were 9: A Mopar-Powered Bug Rod [internal]