I just talked to a muffler shop and he told me that a dynomax muffler is much better than flowmaster 80, and he said it will increase my horsepower by 20+. i think he was smoking too much pipe, but does anyone have an opinion or know anything about this.

 

I would say 20 after a whole cat back is installed. You may have a high flow muffler but you have small un-mandrel bend pipes leading to that muffler. A muffler alone (depending on the condition of your old one) will mybe give you 5-10 hp. But then again it depends on your other mods. My geustimate is for a bone stocker. After I installed my cat back my car didn't feal faster but only smoother. the more mods you get will determine how much HP your exhaust will give ya.


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1990 RS 305 TBI T-5
.5" turbocity spacer
Edelbrock TBI intake
180* stat
Summit 14X3 OpenElement W/k&N
Hooker 3" Areochamber
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/28,000 Pampered miles
(Still have the original wiper blades)

 

true, muffler will add a little, but a system will add a lot more power. get headers and a high flow cat too...

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'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei
'95 3.23 rearend
hotchkis rear suspension