How to mod Holley squirter on Holley 650DP #4011 carb

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Feb 13, 2012
I recently got a secondhand Holley carb# 84016 model 4011. This carb is a 650 double pumper with mech secondaries. After tuning on the street and with a wideband, I had a lean spike when I mashed the gas suddenly from a stop. Seems like I need a bigger shooter. On a normal holley 3310 (4150/4160) this is no big deal...the shooter is super easy to change with 1 screw on top accessible thru the air horn.

Not so for the b*st*rd child 4011. I dont think they make them anymore, and I think Summit Racing actually bought the rights to them. The squirter is actually part of the booster assembly. After talking to both Summit Racing, and Holley, I was told there is no squirter kit available. It comes with a 26 squirter or equivalent....but you will see how it actually works, and what I had to do to change it. Summit offers a kit, that is close, and will almost work, and will work with their own brand carbs of the same style, but not if it has the Holley name on it.

Here's what the assembly looks like taken apart.



Originally I thought this part was what controlled fuel volume out the squirter. This rod fits inside the screw. Fuel goes up the screw, past the rod, and exits the top hole in the screw, where it then goes thru the booster assembly and comes out the shooter nozzle. Turns out this rod/screw doesnt have much to do with metering.


So, I couldn't find any squirter kit at all made by holley for this carb...only summit....and they say its compatible with their carbs only...and they're right. This is what I bought, because it was the closest thing I could find to work with.

This is the installation instructions PDF file from the summit card squirter-jet install kit I got.

Pump squirt volume is actually controlled by tiny little *ss jets that screw into the underside of the booster assembly in the center. Cool. These are the Summit "Accelerator pump discharge restriction tuning kit" jets I bought:


Just so everyone is clear this is the exact style carb I am discussing, but its made by Holley, and not Summit. I believe Summit bought the rights to these from Holley maybe 10 years or so ago.


The problem I faced was the Holley brand carb does NOT have removable jets in the booster assembly like the summit one which looks otherwise physically externally identical. The "jets" in the Holley are actually just a calibrated size brass fitting that is pressed in. This is true for both sets....the squirter ones, and the end ones, which are idle fuel restriction jets. See pic. It's hard to tell from my amateur pics, but these Holley parts don't screw out like the summit me. This is the underside of the booster assembly before I did anything, in factory configuration. See both sets of pressed in brass jets?



So I'm left with an interesting dilema....try to mod my Holley booster to work w/Summit parts, or try to find a booster from a summit brand carb of the same style and bolt it to my Holley (and hope that works/fits) It turned out to be too hard to find a Summit booster without buying a whole new Summit brand carb,

So, on to the modification!

The summit threaded squirter jets in the kit are a bit bigger around in the diameter than the press fit ones actually installed in the I could carefully push out the press fit ones in the Holley Booster assembly, drill/tap and screw in the custom drilled sized ones from the Summit kit I bought.

These were the original shooter jets, pressed in. I heated the alum up with a lighter, and they pried out easily with a screw driver. Stock was equivalent to a 026 squirter according to my Holley manual...which is pretty small.


Tapped hole, didn't have to drill booster jet hole at all, just tap....Summit Jets fit perfectly with #6NC32 tap from my cheapo Autozone tap set.


Jets screw in nice and tight, but don't go deep enough. They were sticking out like this stopping the fuel delivery screw from going into the hole:


So I had to do this and drill the hole a little larger half way down to build a slight step, so the jets would sit far back enough. Also counter sunk the actual jet holes just a wee bit with a 1/8 drill bit. Its a little sloppy looking, but I cleaned it up a bit with a de-burr tool and a re-tap on the shooter jet holes too.


The screw looks like it has enough meat left around the head to seal no problem. I even drilled out the hollow screw slightly, and the exit hole at the top of it, to make sure it isn't a restriction in and of itself so the jet size is the main controlling factor.

Now I have adjustable shooter size! Yay! Stupid weirdo model Holley....grr. Anyways, I think this should work good. The summit kit has all kinds of sizes jets for this, and Holley said they offered NOTHING for this carb! Wtf? There isn't even a trick kit or anything listed in the book....they totally abandoned this model it seems like.

All this to increase shooter size! Went from a 26 to a 31 to try to eliminate a brief lean spike on the wideband 02 and a super slight barely noticeable hesitation at launch when I first stomp the gas.


Thread starter
Feb 13, 2012
If I'm an idiot and did this for nothing, and someone knows where to get access to this crap from Holley without modding the carb, someone PLEASE post your source/part number!!!


Royal Smart Person
Feb 25, 2011
Medina Ohio
I'm not a Holly guy so I can't help you out but I think you would be much better off asking this question on ROP. You might even have some luck on Oldspower too...oh wait, that site's down again. :roll:
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