Wrong, forced induction.
That's what I said man.
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Wrong, forced induction.
For a 5.3 to make 450hp, it would be unstreetable. You'd be torturing yourself as a DD. Reason being, you'd have to choose a crank, piston, and head combo to put you in the @10.5 - 11:1 or greater compression ratio with all sorts of supporting mods like 4-bolt main, 750 - 800 cfm carb or equivilent efi, raised runner/intake, high-pressure fuel pump, blueprint/balance, and relatively large/lopey/poor-street-idling cam, etc. Otherwise, a supercharger might put you close to there on a more or less stock 5.3.
The 5.7 with it's slightly larger displacement could put you there with an ever so slightly lower compression ratio albeit with extensive mods as well.
If you're looking at a brand new long-block swap and are shooting for that power level, i'd look at a 406 (bored/honed 400) for streetable power.
That's my 2 cents. Other opinions may vary.
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