Holley 4779-2 rebuild

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mopowers

mopowers

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When you guys rebuild these simple Holleys, do soak the parts in a carb cleaner bucket, or can you get away with just spraying out the orifices with carb cleaner and blowing out the holes?

The carb I'm building was a good running 750dp, then sat on a shelf for probably 20 years or so. It came apart really easy and looks very clean. It was drained before storing.

I'd like to get it back on the road. I just ordered a rebuild kit along with a new base plate. I just don't have the means to soak the parts.


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depends if I'm in a rush or not. Either way is good, just make sure you blow out all the orifices.
 
I had the same deal with my racecar 4779. I soaked the parts over night and then washed them in warm soapy water. I then shot WD40 through all of the orifaces just to make sure they were all clean of junk and any water. It seems to work fine, but we'll see how it performs the first time out.
 
Any CLEAN 5 gallon plastic bucket, dump in
2 quarts of mineral spirits, dump parts in, wait 24 hrs.
Do what Demon racer says next, clean off gasket residue,
reinstall parts see what happens...
 
Since it was drained and looks clean, i think you'll be fine with the spray.

If you want to make sure you're starting with stock specs, the Holley Tech Library shows the 4779-2 with...

Primary jet...............#70
Secd. jet.................#80
Primary pump nozzle...#28
Secd. pump nozzle.....#31
Power valve..............#6.5

After sitting so long, the only other thing you may do is soak the floats for a bit to make sure there still good.

That's a very good basic carb, I think you'll be happy with it.:thumrigh:
 
Did these carbs have a secondary PV from the factory? I'm guessing no since the secondary jets are so mu larger.
 
I also have a holley 4779-2 and mine did not originally have 4 corner idle, so the secondary metering block did not have a power valve. I am in the process of changing the main body to a proform, and adding a different secondary metering block with idle screws. I'm only going to use this carb to race with though, as now it will have no choke tower.
 
fanofpetty said:
I also have a holley 4779-2 and mine did not originally have 4 corner idle, so the secondary metering block did not have a power valve. I am in the process of changing the main body to a proform, and adding a different secondary metering block with idle screws. I'm only going to use this carb to race with though, as now it will have no choke tower.
Click to expand...

My 4779-2 does have 4-corner idle. It's an ex-race car carb. I'm converting it back to stock to use on my 340.

fanofpetty- What baseplate do you plan on using with the proform main body? If you use the stock 4779-2 baseplate, you'll need to modify it to be able to have 4-corner idle.
 
Does having a 4-corner idle circuits have anything to do with secondary power valves. It was my understand that the PV is for enriching after you're past the idle circuit.
 
Nope. 4 corner idle is it's own deal. It's a good option to have if you have.

When you look at the jetting that came std in a holley 4bbl, if the secondary is the same size as primary, it will usually have a secondary PV. If the secondary jet is larger, then it doesn't.

In your case, you have something that is not stock. If using the factory 4779-2 primary metering block, use the same jet spread as the original, 10 larger in rear, as a baseline.
 
mopowers said:
My 4779-2 does have 4-corner idle. It's an ex-race car carb. I'm converting it back to stock to use on my 340.

fanofpetty- What baseplate do you plan on using with the proform main body? If you use the stock 4779-2 baseplate, you'll need to modify it to be able to have 4-corner idle.
Click to expand...
I'm not sure about baseplate modifications, and thats exactly where I am at, trying to find out for sure what needs to be done if anything. The information that comes with the proform main body does not mention anything, but they do give you different air bleeds to install if there are no secondary idle screws. Maybe someone here knows for sure ??
 
Seems to me member "Coyote Jack" was building some carbs like this recently. Maybe he has some info?
 
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