Is there any advantage in using a Spitfire head on a Plymouth 218 flathd.? I've seen this head on vintage Chryslers, but I've seen it also on some late 40's early 50's Plymouths. I'm under the impression that the Chrysler is a long engine and the Ply. a short. Are there 2 versions of this head or did some of the Plys. get the long engine? Thanks 40 plyguy