5.9 magnum, 500 lift 280 duration cam, home ported stock heads, eddy air gap, 750 carb, headers
(there's a limit to how much you can go over .500 with magnum heads before coil bind and expensive aftermarket keepers + keepers or machine work enters the chat so keep that in mind)
but that should be darn near 400 on the money
wanna make it with less cubes? better heads and more compression.