Good Evening All, Charette reporting in from Carlisle. It was a beautiful day here and I just got back to the motel. Man, am I pooped. Just to add a little grist to the 413 discussion mill, I wanted to suggest we not overlook the benefits of the "squish and quench" provided by the closed chamber of the older designs. Even with the same compression, the squish adds much to the activity of the combustion chamber. (It's after 11pm, and I can't for the life of me remember what the quench did... I used to know that. [It's 11pm, do you know where your mind went?]) Also, is it possible that the casting mass and cylinder wall thickness contribute to quieter operation? Anyway, I always wondered if there was some reason (other than the convenience of measuring in 1/16ths of an inch) that the Chrysler Engineers chose 413 cubic inches. It's sure not like "413" rolls nicely off the tongue, or that it has any other special significance I can think of. And I can't imagine the marketing people jumping up and shouting "Make it a 413!!". Is it possible that it just turned out to be a "sweet" combination of bore to stroke ratio, rod length, intake port length, etc??? Certainly the later 426's and 440's worked well for high performance use, but wasn't the 413 originally intended to be a smooth, quiet, powerful piece for Imperials and the like? And if I'm all wet, why did they continue to use 413's well into the 70's for medium duty truck use? Why not just use the common 440 at that point? Thanks, Steve Charette Imperial Services www.imperialservices.net