Can anyone tell me what the stock jets and squirters are on a stock Holley 4779 - 750dp??

Also, what's a good baseline for the idle/mixture screws in all four corners to get running on a mild 340 with X heads??

I have this carb that used to be on a 8 sec front engine dragster, but it needs a rebuild. I want to replace the edelbrock carb on my 340 with it. I realize it may be too much carb for now, but I plan on replacing the current X heads with a set of RHS heads and a nice solid lifter cam.

primary jet 75
secondary jet 76
power valve 8.5
primary discharge nozzle .025
secondary discharge nozzle .032

idle air screws i usually start at 3/4-1 turn out and adjust from there

those are the "as shipped" specs from holley for a 4779 if it is a 4779-1,2,3,4,5,6,7 or 8 that all changes other than the idle screw adj.

Look it up here. R4779-*

http://www.holley.com/data/TechService/Technical/Carb%20Numerical%20Listing.pdf

You have to include the dash - if there is one, IE 4779-3

The choke's been milled off, but the primary metering block and base plate booth have a 4779-2 on it, so I'm assuming that's the main body was/is... It's got four corner idles, so I'm not sure what the secondary metering block is. I just want to rebuild it and get it running better than the current Edelbrock that's on it now.

Those jets seem a little on the big side for a mild 340. Should I just start with those and tune from there ya think???

Post apicture of the throttle linkage, you may have a 4779 original with no dash number, on the 4781(850DP)the original had different throttle linkage than the later dash carbs did, dfferent jetting also. BTW, Holley has made some later dash # like the -6 or -7 and later that had four corner idling on them stock The later 4781-7 work excellent out of the box You have a job ahead of you I have a Holley 850 that has the choke tower removed so I don't know which version it is,it had problems with the guy that had it before me, I took it in trade hoping to be able to make it work good but I haven't succeeded yet Maybe this summer after the Duster is gone

Ill take a picture tonight. On the top of the carb, it's got the number 6 3752 B. Not sure what these mean other than a 750 DP from what research I've done. The throttle plates say 172 on the primaries and 173 on the secondaries. They are also drilled out and are opened up to where the circuit slots are showing in the ventures. I imagine I need to close them down a bit. Again, this was on 8 sec N/A 355 chevy front engine dragster. The squiters have been drilled to something crazy like 58s, so those definitely need to be changed. The jets are a reasonable 76 on the primary side- haven't checked the secondary side though. The primary power valve is a 25. I can tell the outer air bleeds have been opened up as well. Will this be a problem when trying to convert it to run on my lowly 340???

So, I started rebuilding this carb. It is in fact a 4779-2 carb that has been converted to a 4-corner idle. Is that why this caulking type material is in these grooves? Should I take it out and replace it with something else. The grooves seems to lead to holes under the butterflies that I'm assuming are for the idle circuit.

How should I deal with this? I have all the parts to convert this carb back to stock, but I also want to keep the 4-corner idle.

The red arrows point to the grooves I'm talking about.

Not sure about stock but on my old mild 340 swinger I ran 72-78, 6.5Pv and 25 squirters. Ran great not rich at all. 13.80's and 17mpg.

Jet size depends on airflow through the carb. There is not much, if any, dependence on engine size.

r.