Your next concern would be to throw as much as you can to the trans, get as much billet internals that you can afford. A single disc works well, a triple even better.
You could do about 600+ with a single then have a couple hits of N.O.S. for the strip. Bringing that HP number up..
Building up the trans is paramount to transferring that power to the ground, otherwise it gets lost and will take parts in the system out in the long run. You will need a very healthy lift pump to keep the VP-44 supplied with plenty of fuel, a bigger suction line in the tank pickup, larger feed line, larger inlet fitting on the VP ect..
There are some nice singles that will support 600 on a VP equipped engine and still remain somewhat streetable.
Your very first hurdle is the driveline which most important being the transmission.