Sheesh..stock early 440's were only rated 375. I have put a few projects together but never put an engine on a dyno and am normal pretty skepticle especially of the magazines.
I know this is for a warm 356 sm blk with Dart heads but have a look at comps own dyno numbers.They are interesting for sure,especially the 262!
COMP Cams® - Camshaft Dyno Results