I was asked this yesterday (actually how to double the HP) and didn't have the answer....... I know it can be done with the stock crank and pistons, so I humbly ask here.

What are the procedures, specific parts and names that are recommended?

I personally would go with a Magnacharger with an integrated intercooler.Bolt that sucker on,get the 2" cowl
induction hood and drive it like you stole it!Getting 500 horses is easy as long as you got the cash.
Twin turbos also would work but all that damn plumbing and then you have to worry about isolating the heat from
the turbos even with the STS rear mount systems.
The cheapest way would be aluminum heads,cam and modify your fuel injection to handle the extra air and fuel.
You can get close to 500 horse that way but beware of drivability issues.Super Chevy took a 305 roller lifter moter
with a carb and made an easy and reliable 350 horse and ft.lbs. of torque.This was with a bone stock junkyard LG4
block.Next month they are going to work with a TBI intake on the same motor.
Years ago 500 horse would not have been very streetable but today its easy to do and drive it everyday with reasonable gas mileage and reliabilty.Smooth idle at stoplights and plenty of vaccuum for the brakes.
OK thats my 2 cents!
Take Care
Flasheroo

I have a GM846 cam and decently ported heads with 1.6" roller rockers and I'm north of 400 horses at the crank.

Are you talking crank horse or wheel horse?

Forced induction may be your key. I think you could get it NA, but the car wouldn't be very streetable and you'd really have to rev it to see that number and you'd need a ridiculous converter to make it move.

Are you just hypothetically looking at the HP number or do you have a goal to meet at the track? Don't get stuck on a number if you have performance goals instead. There are other ways to make these cars fast and NOT have a 500HP motor, but will act like it does on the track.

Hypothetical. Like I said, someone said something about how to double the HP and I didn't know the answer. I would ASSume it would be N/A, as forced induction just screams power. I kinda like the sleeper look [You must be registered and logged in to see this image.]

I have heard about the GM846 crank. I was BS'ing with my son talking about a rusted out white woodie with a big block and a T56 with open headers FTMFW!!!!