383 with Eddy heads!
My heads flow in the 260 cfm. range around .500" lift, however, my cam only makes about .450" lift, so I'm not using all of them. The good part is, with the tiny cam, and the RPM intake, I can shift at 5,000 rpms., and it will shove my 3,350 pound car to low 12's, even with the high end skip it had. For a short stroke motor, it's making decent bottom end, which might help out your heavier truck.