If you wanted a hydraulic flat tappet cam, I would probably go with the 286H or the XE284H(this one would probably be a little better with vaccum) both with a set of 1.6 rockers. If you wanted a hydraulic roller, I would recommend the XR288HR or the 286HR. All of these cams would perform around 2200 6200 in a 383 like you are building. They are extimated to have a slightly higher powerband than that, but that is based off of a 350. With a 383, the powerband will drop around 300 RPM, and the vaccum will increase over a 350 due to the cubic inches. If you want to check out the specs on these cams, the site is posted below.