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 High flowing 4150 carbs 
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Joined: Sun Nov 22, 2015 3:42 pm
Posts: 3
I just had my 517" Pontiac street motor dynoed with a Holley 850DP with the choke horn removed but otherwise stock bleeds,blocks,etc. Fuel curve was stable but a bit rich and kept that way to keep things safe. it started to pull over 1.5"HG at 5000 rpm and went to nearly 1.75 at 6000. It has very good cylinder heads and intake with a moderate duration cam for drive ability.
Using a 4500 isn't an option at this point so I was wondering if some of the QFT/Proform 4150 bodies would help pull a little more power over 5000?
My initial thoughts are to try the 1050 body (which I know has the same Venturi as the 850) with my metering blocks and air bleed sizes matching my 850 since the fuel curve was good. Ive been told a QFT/Proform 950 body would probable perform better than the 850DP even though it has a smaller Venturi so it's an option also. Any opinions on these choices or is it just wishful thinking on my part hoping I can get more out of a 4150 body?


Sat May 06, 2017 11:57 am
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Joined: Thu May 08, 2014 7:47 pm
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Around 1.390 venturi on the 850, where as the QF 1050 should be 1.590.

BLP has CNC profiled center sections as well.


Sat May 06, 2017 12:13 pm
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Joined: Sat Apr 15, 2017 2:25 pm
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The old 850's like 4781 had 1.562 venturi's. BLP can do a 1.630, I just posted a 1.610 Blp I got.


Sat May 06, 2017 12:23 pm
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Sat May 06, 2017 2:30 pm
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Joined: Sun Nov 22, 2015 3:42 pm
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High flowing indeed! Never seen these before. Are they 3 circuit? How would they work on in a street app and where do you find these?


Sat May 06, 2017 2:58 pm
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Joined: Sat Apr 15, 2017 2:25 pm
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The bodies can be used for three circuit but mine is just plugged. Will be two circuit. BLP is in Florida.


Sat May 06, 2017 3:35 pm
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The black/purple is a Little Bo, oval blade that flows 1220 CFM dry, just below a 1050 Dominator. I still have two bodies and baserplates to build, along with another one like above built for E85 I use when not testing carbs.

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Sat May 06, 2017 4:24 pm
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Joined: Sun Nov 22, 2015 3:42 pm
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jmarkaudio wrote:
The black/purple is a Little Bo, oval blade that flows 1220 CFM dry, just below a 1050 Dominator. I still have two bodies and baserplates to build, along with another one like above built for E85 I use when not testing carbs.

Image

Any flow figures for the standard baseplate version like Stuska1 is using? In your opinion would there be a noticeable performance gain over a 850 body?


Tue May 09, 2017 8:55 pm
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Roughly 100 CFM less, I have not hat a body on the flow bench in a while.


Wed May 10, 2017 9:24 am
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Joined: Mon Jul 25, 2016 6:14 pm
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Wow Mark, that carb is very impressive looking. Are the outer air bleeds actually slightly angled or is that just the photo? Keep up your excellent workmanship.


Wed May 10, 2017 7:09 pm
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