14-71 Blower openings

Looking at a couple different 14's, wondering what the deal is with the different standard openings (not talking about the retro deals), seems some of the blowers I've looked at have the bottom opening about 1/2" further ahead than others, and the blower would have to sit about .800" further back to position the snout in the same spot. Is the further ahead opening a sign of an older case, or just a different style case?

 

The one that's 1/2" ahead is a retro. The others are a delta

 

See if someone will let you look at a $ 28,000 roots. Lots of changes. I tried to sneak a peek yesterday. No luck

 

The outlet size and shape can be used to tweak the efficiency for different overdrives. I have seen a few different designs for different blowers. Usually the shape has more to do with what works best for the rotors used but playing with it can change outlet temps and fuel distribution as well. Generally speaking all of the unit I have had Mooneyham HH, LF K-8 HH retro non setback, Kobelco K8 HH retro non superman, PSI HH retro 1" Setback, PSI HH retro 2" setback rotors, SSI F-3 HH retro w/ setback rotors, and my current world record holding modified F-11 Extreme all use a pie shaped port with some slight changes in size and contouring. some DMPE units make this adjustable with shoes but I have not seen any other brands do this though there may be some that do. One of the old mods I saw on my Kobelco K8 was to fill the pocket of the outlet so it was flush to your retro plate that was shaped to match. I was told that picked up the 1/8 mile a bit but didn't hurt the 1/4. I will tell you that on my record holding F-11 Xtreme that went 3.604 at 204.78. The exhaust port doesn't look very different from any other blower I have had save the SSI units which use a different rotor profile and they like to do a good bit of contouring on there exhausts. Hope this helps. Trev