didn't know off the top of my head, but i looked it up
7401:
HPF Off/90/135/180/225Hz
LPF 80/120/160Hz
8401:
HPF 90-225Hz; Adjustable in 5Hz steps
LPF 60-160Hz; Adjustable in 5Hz steps
other than the xover the only other difference i see in the decks is the hu power 60x4 (8401), 50x4 (7401) ...which is insignificant i think the adjustable option is worth the extra $25-30 , you can just run your amps full range and adjust freq's from the headunit //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif