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Another Carb question

Keeper

Keeper

Active Member
Okay a while ago I had pickup up a used Holley 4160 from the local classifieds. The guy I bought it from told me he had purchased it, "Messed with it a bit" but then did not want to "fuss with it anymore" to get it running right, and bought an Edelbrock instead.

Anyway

Its a Holley 4160 600 vacuum secondary. The list number is 8004, from what I can find this was for a 75-76 Olds v8. Its also supposedly a "smog carb"

Now the question. I have a rebuild kit for it and plan on cleaning it up. Anything I should keep an look out for? I did find out that the mixture screws are reversed on this carb. Everyone seems to think that this is not a good carb for any sort of performance, but how bad can it be? I mean, its a 600cfm Holley??

Oh yeah, anyone know the stock jets for this? I have seen anywhere from 68-74!!

Oh again:

sbc 350
9:1 comp ratio
Comp cams 262
700R4
 
Do a web search on "Holley 8004 carb". Plenty of info. Here is one I found with some other links which I did not verify.

In the reverse idle setup which you probably have if the
carb is less than about 25 years old, the mixture is
enriched by turning the screws CW. CCW leans the mixture.
The case you describe would indicate the engine is wanting
more fuel at idle for some reason. This may be because the
secondaries or primaries are open too much at idle causing
loss of vacuum signel at the idle fuel ports. This can
easily happen if you have modified the engine especially
with a performance cam. I suggest you make sure the carb is
clean, the correct metering block and bowl gaskets are
installed and, the float level is correct. Check the
adjustment of the secondary idle screw. When you remove the
car, make sure you check the position of the primary
throttle plates. If you are having to adjust the idle speed
screw (not mixture) to the point that you are startingto
expose the transfer slots in the primary throttle bore, then
you may have to drill the primary throttle plates to allow
them to close more at idle. This procedure is common in
performance engines and is described along with picturesi in
many performance publications including the older Holley
literature. You may want to check the link below for some
basic tuning tips.

Lugnut

http://www.bob2000.com/carb.htm

or here

http://www.fordmuscle.com/archives/1999/12/holley/index2.shtml
 
I myself have not had very good luck with older carbs for all the money in a bucket a new carb is a little bit of piece of mind.
JMO
 
The carb is a smog carb and the mixture screws do work in reverse. My holley books as well as their web site shows that the main jet is a122-632, which is a #63 main jet ( the 2 means close limits). The secondary has a metering plate. Many Holley carburetors use a secondary metering plate with drilled restrictions rather than a secondary metering block with removable jets. Hope this helps.
 
And if you bought a rebuild kit designed for a 0-8004, toss the power valve in the trash, as it will be a two-stage valve.

You can make the 0-8004 work for what you're wanting to do, but it really isn't a performance carburetor.

A 66 jet is going to work a little better for you. The secondary metering plate isn't going to be performance-friendly, so you'll want to keep that in mind. It's going to keep you on the lean side of things. If you can lay your hands on a 0-1850 someone has broken a baseplate on, the primary metering block and secondary metering plate will swap out with the 0-8004 parts and will get you where you're really wanting to be.
 
Alright,

Mike I took your advice. I picked up a couple 1850's at the swap meet today.

So lets see I now have:

1850-1
1850-4
8004-1

Two sets of 63 and one set of 64 jets.

Only issue I can see is the main body of the 8004 is a touch different so that will be the body I use, as the damn thing looks new.

Here is the difference between the two, the 8004 has a little "nub" sticking out of the plate.

17%20April%202011%20003.JPG_595.jpg


Here is the metering plate from the 8004. Looks like hardly anything at all went through there!!

17%20April%202011%20002.JPG_595.jpg
 
If you're talkin' about the brass tube w/the "O" ring , that's the accelerator pump transfer tube. probably an older carb . If you're gonna rebuild a carb, don't try to be different, just do an 1850. my .02


dave
 
+1. With that pump transfer tube, you're married to the 0-8004 metering block. A metering block from one of the 0-1850's will not seal the transfer channel, to pass accelerator pump fuel to the squirter.

I see the cad plate is gone from the throttle plate screws, and the baseplate is extremely clean on that carb. Someone has glass-beaded it at some time or another, so that carb's been around the mulberry bush at least once.

Freshen up one of your 0-1850's and drive on. Use the #64 jets, unless you can get your hands on a pair of #66 jets.
 
Okay so I am going to rebuild one of the 1850's (I really wanted the elec choke of the 8004...)

I bought the conversion kit to replace the metering plate as the one I had was shot and I did not want to fight with trying to match them back up. (and the price was not that much different)

So the new question is:

I have bought the 66 jets for the primary, what jet size should I start with for the secondaries?
 
Keeper said:
Okay so I am going to rebuild one of the 1850's (I really wanted the elec choke of the 8004...)

I bought the conversion kit to replace the metering plate as the one I had was shot and I did not want to fight with trying to match them back up. (and the price was not that much different)

So the new question is:

I have bought the 66 jets for the primary, what jet size should I start with for the secondaries?
Click to expand...
If i'm not mistaken the 4160 has a metering plate on the secondaries and no jets.
 
So I picked up some 67 jets for the secondaries, and a secondary spring kit. I looked at the little cam kit, but damn if I am paying $40 for 3 tiny pieces of plastic!

I will have to see if I can find someone to swap some springs for cams :)
 
I wouldn't fret about changing cams about. Swapping out the nozzle will have more effect than changing the cam. The cam assortment will have several cams in it that you would never be able to use, so it ends up being a lot of expense for nothing.
 
Its been a while on this, but today I sat down and worked on dialing in the carb. I had to wait until after the engine was broken in.

Floats are adjusted,

Idle screws were set at 1.5 turns.

Idle about 800rpm.

So I hooked up a vacuum gauge and started adjusting.

At first I thought the needle was bouncing around, knowing that is not a good sign. Then i actually picked it up off the engine......smoothed right out.

I had black smoke coming out of the pipes and my eyes were watering pretty good, so I know I was a bit rich. (Yes I had the door open!)

What I ended up with seems off to me so I thought I would ask.

The final idle screw adjustments are only 1/2 turn out each. That gave me the highest vacuum at 16.

That seems like the screws should be out a bit more....am I correct or should I just leave it at 1/2?
 
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