maybe im just not looking or searching in the right area but i cant seem to figure it out
i just need to know whats a good exhaust cat-back size for the 5.7? i like to go a little bigger then stock but of coarse i dont want to free it up too much, it will be exiting the stock area so it will be a single out.
thanks for any help


I went with 2.5" on the '96 I had. I had true dual Flowmasters installed and it worked for me. good luck!
2010 Z/71 Colorado C/C
Black 4X4 w/5.3L V8
===============
2007 Winnebago Adventurer
w/8.1L Chevy & Allison 6spd.
Canyon Lake, Texas
My freind went with a 2.5 dual in single 2.5 out flowmaster and 3.0 pipe out stock location and hangers. Good sound not too loud but not queit either. Ran better and a local muffler shop installed for 170.00
Mark - Phoenix
97 Chevy Silverado X-Cab
86 Monte Carlo SS
72 Chevelle Convertible

sorry to cut in with my own questions, but if i can add to this topic it might help both of us. i priced some exhaust shops for custom dual exhaust and this is what i got from them,
- i asked if high flown cats helped, he said not really except for actual performance vehicles
- i asked if an 'H' pipe would help with torque, he said yes but to enough to compensate for the price
- i asked about 1 2-in-2-out muffler or 2 1-in-1-out mufflers, he said that instead of having an 'H' pipe, the 2-in-2-out would act as if there were an 'H' pipe and that if i had 2 1-in-1-out that the sound would pop and crackle (like the cleshe' redneck sound) whereas if there were a 2-in-2-out, it wouldnt.
- he also stated that the highflow cats could and probably would cause the O2 sensors to throw a downstream code or something of the sort
i cant really remember what else was discussed, but i was wondering if any of this has been experienced or experimented with and am asking for some feed back please.
2000 silverado with a 5.3l v8, shorty headers, upgraded plugs, 10 mil wires, magnaflow high flow cats, flowmaster 80 series muffler(2 in 2 out) w/ 18 inch stainless silverline tips. i have a k&n CIA. its a 4x4 z71 offroad package. Ls model.
extended cab 160k miles, truxedo low profile bed cover, diablo sport predator tuner.
reman tranny @ 130k miles
Chris
i was going to get a price on 1 into 2 and have the tips come out at the corners of the rear bumpers but i dont think i want to go that rout anymore. we shall see

i got a price for mine the other day. for 2 magnaflow high flow catalytic converters ($80 a piece) the muffler, 2 1/2'' tubing from the headers, total cost of around $400.
the muffler is a flow master 2in 2out, and like sheep said, my tips are coming out at an angle towards the rear corners. i cant wait
2000 silverado with a 5.3l v8, shorty headers, upgraded plugs, 10 mil wires, magnaflow high flow cats, flowmaster 80 series muffler(2 in 2 out) w/ 18 inch stainless silverline tips. i have a k&n CIA. its a 4x4 z71 offroad package. Ls model.
extended cab 160k miles, truxedo low profile bed cover, diablo sport predator tuner.
reman tranny @ 130k miles
Chris

You can't go wrong with 2.5" flowmasters.
Trevor - Huntington Beach, CA
2007 GMC 2500 4X4
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