Std port Victors, when properly modified work very well....... But they are pretty far down the "bang for the buck" list.

Much higher up that particular list, while staying with the Victor theme would be the std port CNC ported Pro Comp head.
Buy them bare, have the valve job redone, install quality parts..... And you'd be good to go.

However, if you really want to wake up that 500" motor, especially for drag use only......... just step away from the std port heads.

Get the TF 270's and a MW manifold to go with them.