Sorry to put this add but i ordered an American thunder single 3 inch catback from flowmster. Now what series is the muffler that they use for American thunder is it 20, 30, 40, 50, 60, ect. Is the exhaust system good enough for a 305 TPI which has a horsepower range of 300 to 350. Thanks

p.s dnt worry i have TES headers and a free flowing catalytic converter.
thanks

 

it has the 80 series, its some good stuff, very loud.....

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"When something breaks, it gives me an excuse to replace it with a performace part!"
1988 GTA
TES headers
Flowmaster exaust
TB airfoil
165 Tstat
K+N's
JET chip
kenwood head unit, xplod amp, poineer 3 ways
weird rattling noises
dying 350
crappy paint
700R4 on its last leg
hood that won't open

 

i didnt know an 80's series existed wow thanks

 

Vortech,
You should be very happy with that system.I just had mine installed and I love it.It was a HUGE improvement in sound.Even though i just installed a new stereo ,I haven't played it in 3 days just so I could drive around and listen to the new exhaust!lol!By the way it is an 80 series as stated in previous posts. Good luck with your new cat back.

 

The american thudner system with the single in/out muffler is a 40 series (their loudest) The 80 series muffler is the crossflow, single in dual out (standard V8 muffler style) I had the AM system, it was mean as all hell, and looked sweet with the huge pipe under the bumper.

 

i appreciate all your answers. One more thing when i got the flowmaster on the box it said american thunder but i have the one with single inlet and dual outlets im sure its an 80 series but is it as loud as the 40 series.

 

The American Thunder 3in single in/dual out is an 80 series crossflow.That's the one I just got,pn17233, and it's definately louder than the 40 series single in/out.That one isn't american thunder,that's the forceII system.

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1987 Firebird Formula LG4,700R4,WS6,2.73 open rear
Current Mods:Flowmaster 3in. American Thunder cat-back,3in. Catco converter,L69 dual snorkel,K&N filter,roof console,Pioneer 1.5din cd player,BostonAccoustics 4x6plates,eclipse 6x9
ComingSoon! 350 crate motor(caprice),SLP coated 1 5/8 headers,edelbrock intake,edelbrock aluminum water pump

 

force II huh damn i cant wait to get the motor and the flowmaster installed!!!!

 

The American Thunder system is a 40 series single outlet system. Flowmaster also makes a dual outlet system now. The 40 series muffler are louder than the 80 series mufflers. The 80 series mufflers are part of the Force II system.


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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday