thinkking bout getting true duals for my 89 150 lriot xlt with a 4.9 and i was wondering if anybody knew if id loose power or not

 

My experience with loud exhaust on the 4.9L inline 6 is that it ends up sounding like the local farmer's John Deere, or an amplified version of the rice-burners.

The better the engine can breathe, the more power that should be available.

The 4.9L is recognized as a stout, reliable motor with oodles of torque. It's not really a street-racing, high-performance set-up, IMHO.