Changing from std to high helix with delta opening. What other changes?

I'm currently running a std 14.71 on a 506hemi, but am looking to upgrade to a better blower.
If I change to a high helix with a delta opening, do I need to change my fuel system? nozzle sizes? locations?
I currently have 6 nozzles in the hat, + 2 in rear of the blower and port nozzles.

If I go to a HH with delta opening, I was thinking about setting the blower back, so that the opening is more central on the manifold.

How much more is to gain by going to a HH 16.71?

The class I'm running has a bottom cutoff at 6.5, so was aiming to be able to run that reliably and keep rpm to about 7500max. It's a bracket class.

 

A few years ago the funny car I work on switched from a standard rotor open bottom 14-71 to a Littlefield K-11 front discharge high helix 14-71. This was on a 518 fuel headed hemi with centrifugal clutch and 3 speed Lenco. With the old blower at about 40% over it would run 6.60's with a .120 ish main making around 30 lbs of boost. We installed the new high helix blower with the standard 2" setback plate. At 14% over it would run 6.70 all day long but it needed a .065-.070 main. At 22% over it would run 6.40's with a .050 to .060 main. Nothing else major was changed. The front discharge would pick on #1 & #2 first so I increased the nozzles up there. I would recomend moving the blower back further. My new setup has the blower back another 2 1/2 inches. Definitely put more fuel in it.

 

Basically what it comes down to is boost pressure. With every bit of increase in boost you will need to reduce the main jet size to increase the fuel pressure to compensate for the added resistance of the increased manifold pressure. Use the calculator on Spuds FIE website to tweak things until you get the right nozzles and pill required for the fuel pressure needed

It's always best to have your entire system flowed but it can be done if you start on the safe side and work your way too it

 

One thing to keep in mind is that the charge temperature coming out the bottom will be lower with the high helix even with comparable boost levels. That made a huge difference in our case.

 

Thanks for the replies.
I'm just trying to learn as much as possible before I change anything.