l have a 1990 mercury grand marquis ls and ima goin to get a flowmaster 40 is series but this guy told me 2 get a dual chamber will this make it louder then a single?????? or anything else l can do besides this to make it LOUD!!!!????
OH AND HOW MUCH HORSEPOWER DOES A 1991 GRAND MARQUIS 5.0 V8 HAVE???

just knock some holes in your muffler
no need to get any new equipment.

Take off your muffler completely, run a straight pipe from the cat..

FLOW MASTERS WILL GIVE YOU A DEEP THROATY SOUND , IF YOU WANT IT REALLY LOUD GO WITH A GLASS PACK OR CHERRY BOMBS STRAIGHT PIPES

1991 Mercury Grand Marquis
4 Dr GS Sedan

Dimensions :
Exterior
Length: 213.6 in. Width: 77.5 in.
Height: 55.5 in. Wheel Base: 114.3 in.
Curb Weight: 3836 lbs.
Interior
Front Head Room: 38.3 in. Front Hip Room: 57.6 in.
Front Shoulder Room: 61.7 in. Rear Head Room: 37.2 in.
Rear Shoulder Room: 61.5 in. Rear Hip Room: 56.9 in.
Front Leg Room: 42.5 in. Rear Leg Room: 39.7 in.
Luggage Capacity: 21 cu. ft. Maximum Seating: 6

Performance Data
Performance
Base Number of Cylinders: 8 Base Engine Size: 5 liters
Base Engine Type: V8 Horsepower: 150 hp
Max Horsepower: 3200 rpm Torque: 270 ft-lbs.
Max Torque: 2000 rpm Drive Type: RWD
Turning Circle: 39.1 ft.

Fuel Data
Fuel
Fuel Tank Capacity: 18 gal.
EPA Mileage Estimates: (City/Highway)
Automatic: : 17 mpg / 24 mpg
Range in Miles: (City/Highway)
Automatic: 306 mi. / 432 mi.

Just take off your muffler & stick a sign in your back window that says: ''PLEASE ARREST ME''. :-)