I am getting ready to pull the trigger on a used blower to run on my Cp tunnel this year. It currently has a very well prepped 6-71 which cavitates badly and just cannot supply enough air for my 400ci SBC. I was thinking of getting a 8-71 hi-helix with the delta opening on the bottom. Enough blower? Dont ask, you will laugh when I tell you how much power I want to make. It will be running on corn and the long block can pretty much withstand anything I can throw at it.