Only 460hp

This isn’t a recommendation to change anything, but are just thoughts on “why” it makes what it makes.

Did you have the heads flowed, or is that an advertised number?
If it’s the advertised number...... it’s probably optimistic.

CR isn’t as high as it could be, especially if it had been built with quench.

Cam duration is fairly short for a combo that has smallish heads(for the displacement).
Those 4” crank combos can easily use up a short cam.

You should post up the sheet.

I agree with Brian........probably the easiest way to 500+ is mill the heads, more duration, and maybe a Victor intake.