Heads are gonna make or break your combo with weaker heads (.300"-.500" lift flow numbers) you'll need more cam and cr with better flowing heads can get away with less cam and cr.
The so called magazine 400hp combo there like 4 of them, basically are an 750 with airgap, headers, 230 cam, 10:1 cr and magnum heads or a 230 cfm LA basically mild ported with 2.02 valves. If you want less cam need the heads to do more work by having better .300"-.500" flow numbers.