There's a company that sells an LS conversion by vorshlag for old 3 series BMWs. Maybe that would work. The LS is aluminum so it doesn't weigh any more than the 6. Jeff 6559 On Mon, Jul 30, 2012 at 2:52 PM, Sean Korb <spkorb at gmail.com> wrote: > I want to put a 351C in my sweetie's 635csi so badly I'm gonna need therapy.