Help with my first engine build (5.9 Magnum)

ValleyRat said

That's great information. I 've been told that the stock Magnum cams are very whimpy, but wasn't sure when I would have to start worrying about upgrading keepers and retainers with my choice of new cam. Its nice to know that I'll be able to use stock components (aside from valve springs).

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I THINK the Mag 380 crate motor used stock valve gear aside from springs (which you covered), with its cam, which is more aggressive (.501/513", 288/292) than yours.

And note: with what was essentially a truck long block with headers, 9:1 squeeze, and a hot cam, they made about 400hp. (I suspect that 380 was the lawyer-friendly number.)