Everything you ever wanted to know about cross rams can be found at the Chrysler 300 Club web site. http://www.chrysler300club.com/ The section on rams: http://www.chrysler300club.com/uniq/allaboutrams/allaboutrams.html Bob Merritt Subject: Re: IML: Cross rams > This is called "tuned" manifold, and one can improve volumetric > >efficiency (possibly over 100%) with the tuning effect. The bad news is > >that > >the tuning is most effective for one engine speed, and the effects trail > >off as > >you deviate more from that speed (and can actually can reduce performance > >for > >speeds too far from the target speed, wither too high or too low). >