HOLLEY 950 HP

[cdr]

just a heads up, everyone has said that 950 HP Holley has the small  1.375 venturi with 1.750 throttle plates, but the one I have has this.

950 CFM Street HP Carburetor

Mechanical Secondary

PART# 0-82951

   Specs

Barrels   4
Booster   Down Leg
Brand   Holley
CFM   950
Choke   None
Emission Code   3
Finish   Shiny
Fuel   Gasoline
Fuel Inlet   Dual
Material   Zinc
Model   4150HP
Product Type   Carburetor
Secondaries   Mechanical
Supercharged Application   No
Throttle Bore   1.750 inch
Venturii Size   1.563 inch

   

[BSB67]

Holley original 950 had the small venturi.  And I think you can still get it.  But 950's today come with 1.375, 1.400, 1,420, 1.450, and 1.560, depending on the supplier.

In my opinion, the 1.560 with conventional downleg boosters has limited practical use.  On paper, it sounds like the best, but that large venturi really softens up the main signal.  If you think you need that, you should also seriously consider a Dominator.  Not that it doesnt have some application, I just think it is narrow.  The 1.560 does get a lot better with annualar boosters.

I've run both a 1.375 and a 1.560 venturi on my car.  The 1.375 was faster, and better to drive.  I know of one other case like this as well. 

If I get another one, it will be a 1.420.  There is a well known head/engine builder/dyno guy that has an 1.420 carb that is his that he trys out on a buch of stuff.   His general conclusion is that it make the most power on a large range of motors.

[cdr]

yep I have been having tuning problems with the large venturi, I swapped the body for one with AD boosters & it did help a lot.

[john108]

I saw this on Moparts:

Holley 750 HP...1.375 X 1.720
Proform 750.....1.375 X 1.720
Holley 950 HP...1.375 X 1.750
Proform 850.....1.400 X 1.750
Proform 950.....1.450 X 1.750

http://board.moparts.org/ubbthreads/ubbthreads.php/topics/552195/re-950-proform-venturi-size.html