I don't remember if they are the same head (I don't think so, same design though). Last spring I was leaning toward the GMPP combo (I don't remember exactly why though

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In my case (on a relatively stock 350) I found a pr. of used Vortecs (complete and checked for cracks) for around $250 pr. Complete swap, Intake, cam, gaskets,bolts, fluids, etc was about $700. You don't think about it, but a tube of sealer, couple gaskets, case of oil and other items add up quick.