We had a 71 Charger factory slant 6/904. It was pretty much a slug at getting up to speed, but once there it was a great cruiser.
I was tempted to do a built slant 6 with triple Webers for the engineless 67 Charger I bought a few months ago. It was that or a rebuilt Gen I 392 Hemi I have sitting on the stand. A slant with triple Webers would look good, but the Hemi looks even better!