I have good things to say about the 400 also. A bigger 383 with low compression. I had a 73 from a C-Body I put in my Challenger with a 727 and 3.55 8 3/4. Rebuilt .030 over, 9:1 pistons, 383 Magnum cam & intake, electronic ignition, headers and a Holley 650 spread bore: great on the street...