How much difference in high helix blowers?

As there isn't much price difference between a 14.71hh retro and a 16.71hh retro, would I be better to go to a 16.71. Engine is 506hemi with 14.71std running 44%od atm. I'm only shifting at 7500rpm.
I was thinking if I used the larger blower, I wouldn't need to spin it as hard to make the same boost and hopefully it would be more efficient and also less intake heat.
Am I thinking in the right direction here, or am I missing something thats gonna bite me?

Whichever way I go, I was planning on setting it back to get the opening as close to centre of manifold as possible.

 

Rule of thumb is, if both blowers are identical, going one size up it's about a 6% difference, as far as us building a 16-71 LB-20, we can't do it, our machines are maxed out with the 14-71 LB-20

 

Andy, Are the Littlefield 16.71 blowers a std or high helix?
And what is an LB-20 blower? Is it a new design or does the 20 stand for HH series?

 

the LB-20 is a new design, it has inset bearing plates, 2'' in frt .200 thousands rear, the top opening is forward of the rotors and directs the airflow into the cavity of the rotors to let more air in per revolution. The bottom opening is a frt discharge but is built into the case, it was designed to be put in the stock manifold location, but there again everyone has their own idea on setback, we have both std and high helix designs, we have had this on the market since aug. of '08 and have seen very good results, besides more boost, blower efficiency (parasitic loss) and lower manifold temps are the other reasons for increased power

 

as far as making a LB-20 16-71, we can't do it, our machines are maxed out on travel,the LB-20 14-71 is the biggest we can make.

 

So, if your machines are maxed out at 14.71 length, any 16.71Littlefield would be a std then? Is that right?
I have got onto a Littlefield 16.71 for a good price. It has a delta opening in the bottom. The opening in the top is 10 1/2" long. The plate that comes with it, sets it back 8". It has a 12" snout. But I'm assuming from what you say that it would be only a std helix rotor in it.

I'm only looking to try and pick up 3 tenths, from 6.8 to 6.5, as the bottom cut on the class I'm running is 6.50.
I'm currently running a 14.71 at 44%od, with std rotors and openings on a 506 hemi.
Do you think the 16.71 will give me enough extra to cut down on the od some and still be able to get to 6.50's?

 

the 16-71 is a high helix you have with a delta bottom is most likely a high helix, the only reason we can't make a 16-71 LB-20 is the case length, not the rotor length

 

you could most likely slow your overdrive down about 10%, be pretty close with your tune up and get the ET your looking for

 

OK. Thanks very much for your help Andy.

 

Interesting discussion.
Is a 14/71 Littlefield High Helix Retro blower with K11 rotors a good blower?