why is it that they are labeled as 93-97 Lt1 in jegs and on thunderracing.com, when the cat hookup is different for dual cats and single cat cars? is the 15620 part number system what im looking for? its a 1996 Z28, thanks!

http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

(i dont want the converter since i have dual cats, just to show what system im talking about)