I'd go with the Holley 600, but if you're running a spread bore manifold I'd run a short four hole spacer to square the plenum opening. Holley's don't transition to well on spread bore manifolds. Go to www.summit.com and check out the Holley kits. There's a kit that has different accelerator pump shooters and cams to tailor the accelerator pump which IMHO is the way to go. I'd also consider the secondary diaphram kit which makes it easy to change when the secondaries come in. You can also opt for the kit that changes your 4160 to a 4150 by replacing the metering plate with a metering block for the secondaries.