I personally didn't notice a larg4e drop of power or torque when I added the Off Road H and cat back to my stock motor. Althought I do agree with the back pressure comments, a Flowmaster needs 13" of pipe after it to get the proper flow from their mufflers, all per Flowmaster. I personally like my MAC's much better then the American Thunder system I had, they fit like crap and rusted after a short time, my MAC still looks new after 2 years or so and the fit was great, just my .02
.
------------------
Check Out My Site 91GT,Holley SysteMAX II Kit-Heads 2.02" x 1.60" port matched to a 1262,Anderson N-61,24#,76mm C&L,Full MAC exhaust 1-5/8" Long tubes,2-1/2" O.R H-Pipe,2 1/2" cat back, No A/C or PS or emissions, 12" K&N Filter,RNH PERFORMANCE Ram Air,Ron Davis Radiator,Full Suspension,S&W 8pt "X" brace,JAZ seats,3:73's,Welds..etc,4:30's and 31 splines coming very soon!
FIRST TIME OUT 12.16@111 WHEELS-UP