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Customer q:

I have a '89 formula w/ a tpi 408 stroker I need a catalytic converter to get a sticker. I was looking at getting the Flowmaster 2230125, but it says only good up to a 360cu.  I have a sinister exhaust 3" to a 4".  Single 3" to 4". W/ a spin tech muffler.  Will it work w/ 408? Why is the flowmaster rated to a 360 cu? 389-2230130? Thanks


make = pontiac

model = formula firebird

year = 1989


Sinister offers nothing for their exhaust. You want a single catt at 3''. I suggest either one of the ones shown below that has the best fit. That is what they rate it to. They do the testing and have to give it a number. If you need further assistance, we are here 24/7. Have a good rest of your day.

Kooks Custom Headers GE-307540
‍High Flow Race Catalytic Converter 3" x 7.5"

Kooks Custom Headers GE-3010540
‍High Flow Race Catalytic Converter 3" x 10.5"

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Posted on
May 10, 2018
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