Piston454

everywhere i have read people say to never use 454 injectors on a 350. but i feel like my 400 is pushing the limit of those injectors because my car falls flat on its face in the higher rpms. yes i have a tuned chip for my ecm. and can do my own tuning. but i am a beginner so keep that in mind. should i run 454 injectors. my 400 is a mild build pushing 400 hp at the crank. running 11.5 compression. i have tons of other modifications that i dont want to list but i have done a ton of research and i feel my setup is either lacking air or fuel. any pointer or advice on tuning or parts would be great. i dont know what my fuel pressure is at but i know i have it turned up higher then stock, i need to get a gauge so i can see where i am at for sure.