My question is "why do you want to change...there is not flow increase, etc ..... nor is there really anthing such as a "high Flow cat" in the aftermarket world.............. Here's a link to a "Real Test" that verifies....on a700+ hp engine......no gain or loss of with or without the cats!
http://www.kennebell.net/KBWebsite/Common/pdfs/header_cat_xpipe_exhaust_tests.pdf The myth about high flow cats http://www.catalyticconverter.org/news/news_page.cfm?Key=catalytic_converter-&News=89 Under federal regs………up to $2,500 for modifying any emissioncontrol device….and lets face it, for the few hp (if any) you will gain byswitching to “high Flow Cats”, that $2,500 can buy a lot of real performance! Straight from the EPA's page and the Federal law trumps statelaws, it might pass emissions but ever get a cop with “wanting a reason” foryou and you can get hit pretty good. http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf
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