Holley Supercharged Carbs

[JLaughreySS24]

Does anyone know or have any experence with these carbs from holley? Holley says they are their line of carbs for superchargers that have a manifold referenced power valve. Are they referring to boost referencing? If anyone wants a part number here is one for the 950 cfm 0-80577. You can get them in a 600, 750, 1150 cfm also. There are two fitting on the side of the body of the carburator that looks like you would hook up to the manifold. For boost referencing??? I dont know but maybe someone else does. Thanks

[sgdiv7]

I have a pair of them sitting on top of a 8-71 and they work great. Yes, the tubes that stick out of the side of the carb are boost referencing ports that you run a hose to the intake manifold (under the blower)they asure that the motor does non run lean at part throttle low boost. The carbs come with #5.0 power valves in the primary side and none in the secondary side. Nice carbs but pricey though. From what I know now I would just coppy them the next time could most likely save one hundred a carb or more doing the modifcations yourself. Those carbs went up $75.00 a coppy sence I bought mine.
Bill

[sgdiv7]

http://pstr-m05.ygpweb.aol.com/data/00A/31/73/1B/D5/3tjolOr+95aV1BtSD1JWbsiy7T3GuMHc0180.jpg
[This message has been edited by sgdiv7 (edited March 16, 2002).]

[JLaughreySS24]

Hey sgdiv7, thanks for the info!! Do you know why there is only power valves on the primary side and not on the seconderies?? Thanks for the photo too.

[sgdiv7]

power valves would not do any good on secondarys because by the time the secondarys open manifold vacuum would be so low (under 5.0 vacuum)the power valve would be open befor the plates even started to open, so there would be no need for them because of the progressive throttle linkage. Maybe if all 4 opened at the same time like tunnel ram carbs they would work then. Better the way they are now, less moveable parts to mess up or whare out.
Bill

[Sinbad]

On the intake where did you tap for the vacuum port. THANKS Bill

[sgdiv7]

I mounted mine next to the pop off valve on the intake (weiand manifold) you can see it in photo I posted.
Bill

[Infomaniac]

[QUOTE]Originally posted by JLaughreySS24:
Do you know why there is only power valves on the primary side and not on the seconderies??
The main reason is the power valve is for economical operation. Lets you cruise economically and adds more fuel at high power settings. If you are into the secondaries, fuel economy is not an issue

[RumRunner]

Actually blower carbs should have 1 to 1 linkage on them to give you better fuel distribution in the engine, and a PV in the secondary side is a good idea. The PV adds fuel to the main jet well when the vacuum drops below the rating on the valve, since the idle circuits pick up there fuel out of the main jet well if you have a leaner main jet (6 to 10 sizes with a PV) you'll have less fuel at the idle circuit, giving you a cleaner, more responsive idle.

[gnarley]

Originally posted by sgdiv7:
Nice carbs but pricey though. From what I know now I would just coppy them the next time could most likely save one hundred a carb or more doing the modifcations yourself.
sgdiv7, How would you copy them. I have a single 850 that I might like to change to boost referencing. Maybe you could post the method with instructions for the rest of us to see.
Gnarley

[sgdiv7]

the next time I have them apart i'll measure everything and do that. I think the two most important things are, the 4 corner idleing and boost ref. Boost ref. plug normal vacuum port and drill opposite of linkage through side of main body into power valve chamber and put a metal tube in the hole and run that to the intake manifold. In order to make the secondarys flow fuel at idle copy the primarys. put down leg boosters in all 4 venturies. The rest of the stuff is just your normal holly tuning. Drill holes in butterfly so idle circuit don't dry up. if you need more fuel then that drill the idle feed hole in the metering block .002 at a time until it fixed. this will help get rid of the off idle stumble. bigger shooters helps also, do them first. Its all trial and error. When I put these carbs on for the first time I still had to enlarge the shooters And make the holes in the butterflys smaler because it idled way to high. If you can do all this stuff yourself you can save your self money. I was a normally asperated kinda guy before this motor.lol
Bill

[StealBlueZ]

I just ordered a pair of Bigs 1050's for my 509. They will be boost referenced on the primary's AND the secondary's. This is for a lake boat, and if needed, I can plug the secondary PV, and learn as I go. Check out http://www.fordmuscle.com/archives/2001/09/bigs/index.shtml. The cost on these are a little cheaper than a blower carb from Holley, and I think there's a little more bang for the buck from Bigs.