Does anyone know if the later VVT blocks (6.1/6.2/6.4) can be machined to accept an '03-'08 cam without the cam phaser deal?

I'm initially going to build an early 5.7 w/carb (rules) for my dirt car but would like to see if there's a way I can finagle some extra cubes without going to a longer stroke than a 3.79... the hot set-up in these endurance deals seems to be a big bore/short stroke motor.