This was probably true at the time. And, those original hemi heads were hard to pull for any needed maintenance. But, Chrysler brought out hemi's again, twice. Insurance surcharges, emission issues and public/governmental sentiment probably killed the second one. The third hemi took full advantage of the historical performance success of the first two and has been a major marketing success. And, the success of the new "semi-hemi" has raised the interest in and prices of all old hemi-engined cars. Win-win, methinks. As previously discussed, higher volumetric efficiency=more air=more HP. A full hemisphere has twice the area of a circle of the same diameter, allowing bigger valves and higher volumetric efficiency in a hemi. The tuned rams helped offset the air capacity loss associated with smaller valves in the wedge. Current technology also includes variable valve timing, multiple valves in the heads and variable length intake manifolds to get more air into the combustion chambers. And I see at least one vendor is making hemi heads for Shivvy's! Mostly progress, with a few backwards steps. C-300'ly Rich Barber Brentwood, CA 1955 C-300 2005 Dodge Durango Yeah, they both got Hemi's -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of John L. Chesnutt Sent: Friday, September 28, 2007 9:35 AM To: 'christopher beilby' Cc: chrysler300@xxxxxxxxxxxxxxx Subject: RE: [Chrysler300] Carbs and clay Hi Christopher, The 392 engine was discontinued by Chrysler because it was too expensive to make and weighed too much. The 413 cost less to manufacture. Hemi's produce more power per cu. inch. John Chesnutt, 1957 300C in Portland, Oregon. Owner since 1958. To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/