My holley 650 is a spreadbore with mech secondaries. It doesn't have a set screw on the top of the fuel bowls. It must be an earlier model. How do I adjust them? Thanks. ------------------ 1986 CAMARO Z28 -> 151,000 original miles, 43,000 on 89' vette 350 block, Holley 650 DP, Weiand intake, 1.6 rockers, 1 5/8" headers, no cat, 2 1/2" Flowmaster catback, Mallory coil, March pulleys, B&M Ripper shifter, T5 with 3.35 1st gear and 0 miles, 90% Centerforce clutch, 3.73 posi, Eibach 1" drop springs, Spohn LCA's, Spohn adjustable panhard rod, Subframe connectors, all bushings are urethane, 2 12" Sound Streams, 2 Infinity 6X9's, 2 Pioneer 6X9's, 800 watt Lanzar Vibe amp. ET 13.32@ 106.4MPH 3300lbs less driver and speakers Next mods-> Extreme Energy 268 cam, Holley street dom intake, ported heads. 1987 TRANS AM -> 73,000 miles, 305TPI, auto, gutted air box, gutted cat.

I was fairly sure that all the holleys had float adjustments on the top of the fuel bowl , Ive never heard of a spread bore with mechanical secondaries at least a holley made one. You could pull one of the fuel bowls off and see if there are adjusters internaly. Is there a sight plug on this carb?? I wish I could be more help but if there isnt adjustment provisions on the top I doubt anyone here has seen or delt with this kind of holley before. You could always email holley and find out what the deal is?? Im confused also.
SSC

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Next project, retrofit the primary propultion system from the ufo that didn't crash at Roswell into my camaro.

I've seen internal adjustment floats in the old Lemans fuel bowls - I'm not so sure that's what you have though. Holley did make a 450cfm carb that looks just like a Q-jet,, and it could be called a spreadbore, it has internal float adjustments like the quad. The way it's adjusted depends on whether the fuel bowls are attached to the carb body with 4 screws,,, or if the top of the carb has to be removed to get to the float. Speaking for myself, since I'm not really sure exactly what you have,, I'm relunctant to tell you how to adjust it. The number off the carb,,, or a picture would help. Hard to say 2,000 miles away over the internet with no more than you given so far.

Ooooh yeah that carb. I've had one of them. does it say 6210 on the choke tower? has stubs on the side that look like it should have an adjusting nut for a side hung float there but it's just blocked off?

They don't have an externally ajustable float. The only way is to take the float bowl off, and adjust the float up or down by bending it up or down. a rebuild kit for it should come wih specs to measure how far from the bottom it is, or you can guess.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

I just bought this carb.
It is a Q-jet replacement model 4165/0-6210
For the person that wanted a pic,
here you go.




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LOBC-- SS-84

92 RS Heritage package with a 305
84 El camino

JDMZ28, is that the one you have? If so they are internaly adjustable "you have to bend the floats"


SS-84 those are vac secondary carbs right?

No they're manual secondaries, with 50cc pumps in the secondaries too. The carb I'm using I built using one of them..with standard double pumper adjustable float bowls.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

As jester has said, No they are Mech. secondaries.

I bought this carb to go on a vortec 383 that i built, but It will stay in the box until I build something else. I put a 750 on it after reading a lot of discussions on this board.

Yes, that is my carb. Almost identical. Personally I love the carb, my car is fast as hell since I installed it.

Now, how do you adjust the floats? I have no prior knowledge on these so please be as discriptive as possible. What do I bend and how do I know what direction to bend it.

If you guys want I will refer to it as the "quadra-holley".

Thanks.



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1986 CAMARO Z28 ->
151,000 original miles, 43,000 on 89' vette 350 block, Holley 650 DP, Weiand intake, 1.6 rockers, 1 5/8" headers, no cat, 2 1/2" Flowmaster catback, Mallory coil, March pulleys, B&M Ripper shifter, T5 with 3.35 1st gear and 0 miles, 90% Centerforce clutch, 3.73 posi, Eibach 1" drop springs, Spohn LCA's, Spohn adjustable panhard rod, Subframe connectors, all bushings are urethane, 2 12" Sound Streams, 2 Infinity 6X9's, 2 Pioneer 6X9's, 800 watt Lanzar Vibe amp. ET 13.32@ 106.4MPH 3300lbs less driver and speakers Next mods-> Extreme Energy 268 cam, Holley street dom intake, ported heads.

1987 TRANS AM ->
73,000 miles, 305TPI, auto, gutted air box, gutted cat.

Take off the bowl. Leave the float and the inlet needle/seat assembly like they would be in the fully assembled carb. Flip the whole thing upside-down. Shove a 1/4"-3/8" (depending on the spec of your carb) drill bit between the float and the top of the fuel bowl (which will now be below the float since you flipped the fuel bowl).

You simply bend the float arm "tang" that pushes on the inlet needle valve- the little "loop" of metal that actually pushes on the needle valve- not the float arm itelf. I am taking this information from my expereince with more common 600 CFM squarebore vacuum secondary carbs that use a fuel inlet system very similar to yours (by appearance).

Make adjustments to the foat arm tang until the drill bit slides under the float just barely without touching it. The float arm should be just about horizontal with the top of the fuel bowl at that setting. That's how you want it.

[This message has been edited by Damon (edited June 10, 2001).]

[This message has been edited by Damon (edited June 10, 2001).]

I've had quite a number of those, in fact right now I have its big brother 800 CFM 6211 on my 400.

Damon about covered it. usually you can just eyeball the top of the float (which would become the bottom, since you'll have t upside down for this setting) and bend the thing until the float is level.

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"So many Mustangs, so little time..."
ICON Motorsports