power loss in 2nd gen

Had my 89 GTUs for about a month. new motor w3k on it. The other day it lost half it's power. still runs, no smoke no strange noises. but won't rev past 6k and tops out at about 80mph in either 4th or 5th gear. any help would be great

Kind of soudns like you might have a blown engine. does it hit a wall at 6000 RPM?

...1 rotor engine situation?

Check your compression.

i would check the exhaust.

if the exhaust is disconnected in certain spots it will mess with your power, also it sounds like it could possibly be your 5th and 6th ports but I doubt it