so im wondering what my local PERFORMANCE exhaust shop who has been around for years.....is thinking when he told me today i would lose power and be very restrictive by me taking a stainless steel single inlet 3" single outlet 3".. magnaflow 24" x 5" x 8" muffler, and installing it on my 2000 K3500 5.7l. he thinks because my stock muffler is 2.5" dual inlet / 2.5" single outlet by me using a y pipe to install the new muffler it would kill power levels and be restrictive to lose gas mileage!!!
is this true!!??
is this true!!??