Disappointed magnum head flow numbers....

33IMP said
The general rule i have seen, is two hp per cfm is possible. I think that kinda depends on how much motor is under the heads. I doubt a 273 under 225 cfm heads will run as well as a 408.
Forced induction throws that (very!) general rule way out the window.
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The general rule applies whether 273 or 408. However the other general rule also applies pertaining to rpm. Will your valve train and short block handle the required higher rpm to make that power? And both are very simplified generalizations.