Porting the EGR bump out of the exhaust port will help both, torque & h.p. The problem with these heads is that if you grind too far into the exhaust ports' roof you could get into the EGR's main air channel. You should be able to grind EGR port at least flush with exhaust port's roof and not have a calamity. Since you will have the valves out of the head to do any port work, (if there is enough room) try using a tap to make threads inside of EGR port that goes into the exhaust port and then use Locktite Sleeve Retainer & thread in an allen headed pipe plug to seal EGR port. Also seal EGR ports on both ends of each head using the same procedure. A 460 likes a dual pattern cam! Go 10-15 degrees more duration @.050" & .020-.025 inches additional lift, both on exhaust side. The biggest downfall of a 460's head design is crappy exhaust ports! Port match both intake & exhaust, don't do anything within the intakes port, it flows plenty "as-is". The roof of the exhaust port to about 3/4" from the bottom of the port is where you will be most effective, especially at the ports' exit. I hope this helps in any way.

Todd
BB79RANCH