Sooner or later this happens to almost all of us. Don't listen to the BB boys, it happens to them as well (point in case, going from 520 CI motor to a 557 CI supercharged motor.
)
If you put more horse power in it today, tommorrow you will want more. It is a sickness, seek help. Go down to the local speed shop and have them set you up with NOS. Go with one of the systems where you can change the horsepower by changing the rods/jets/whatever. Start with the smallest ones, say 50HP. When you are bored with that, put in the 75HP ones. So one and so forth.
By the time you get to 1000HP shot
you will probably have cooked the motor. But at least you have discovered you tolerence thresshold for HP. So then build a new motor with that amount of HP, plus some for good measure!
Rick