heres the video. i have done his with a 400 and seems to have added a good bit of flow. not hard to do at all and olny cost a few min. of your time.MaxiJet Powerhead Mod - YouTube
here are the out of box mods that you will some people talking about.
#2 Sure Flow Mod part 2 - YouTube
here are some numbers for ya
Maxi jet w/out mod:
maxi jet w/ mod:
1200 2,100 or 1,600
thought i should share some of my research.
how much additional flow did you get with the 400 and the nozzle off /holes in cover mod???