I am running a motor very similar to yours. 8.8:1 or so, merc. rect heads (massaged just a little for flow), and the Merc. dual plane magnum manifold. Last season I ran with a holley strip dominator single plane manifold and I notice this year I have more mid range torque (and I'm running a slightly smaller cam to boot). I'm happy with my set up, have about 24 hours on it now. Oh, and I went with the Merc. intake at KAAMA and Crazyhorse's suggestion. Glad I did.