HP loss through transmission

[sanman]

Would anybody have an idea on what kind of HP can be lost through the transmission. ZZ383 with a couple of changes, dyno'd at 457 hp. TCI 350 streetfighter and a streetfighter TQ converter with a gearvendors. I like how everything works it just feels like I lost a lot of power. Anybody have this combo and what was your experience? Wondering if the GV looses a lot.