Alright people I am in need of some help in the transmission area. My nv3500 is about to take a crap on me which is fine because I am building my engine up to the 450-500 hp range. Obviously the nv3500 wont handle this much. What would be the best route to go for 5 spd transmissions? nv4500? any others?

I have a 93 k1500 5.7l 350