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Hey fellas! I just bought a new carb from ebay. Its supposedly a Holley 850 double pumper, completley redone. Im trying to find an id number to verify this, and buy a rebuild kit. It does not have a choke tower. the only number I can find on the main body is 6R2762 stamped on the top of the carb.
Type #4150
List #4788
6.5 power valves front and rear
#80 jets all around
wow! thanks! how did you figure that out? i did open it up. it doesnt have 80s all around...not sure about the power valves.
Just to add to Tech's specs, it's rated from the factory @ 830 cfm.Quote:
Originally Posted by techinspector1
With the base plate addition, it may breath quite a bit better.
Even Holley underated thier carbs a little so if you tear it down and bring it back to specs, this should be a formadible piece to use.
Your pic shows some "shelf" time and needs to be cleaned up in all the orifices and throttle plates, etc.
so would you guys recommend some kind of rebuild kit to bring it back to specs?
Tear it down carefully first, clean up the rust and crap that's visible in the pics.....orifices in the air bleed department and make sure you rorifices in the metering blocks and base plate are clear and have no junk in them.
The blue metering block gaskets show that there are some resuable parts in this thing.
Tear it apart first and let's see what's in there.
thanks for your advice! much appreciated..i did notice a around the secondary accelerator pump. plus the secondary squirter wasnt squirting fuel...
Actually, I'm pretty sure it is a list 9380... note the big annular boosters... this is the same carb I have... the list number is normally on the choke tower but yours has been milled off (which is a good mod!) These are race carbs for stocker classes and is a very good carb capable of supporting quite a few horses. (best you could get in a 4150 until they recently came out with a 950cfm... but this is the only 4150 that came stock with the annular boosters)
850cfm 78 jets from the factory (all around or "square") 6.5 power valve 30cc primary 50cc secondary accel pumps.
To be sure, you can check the throttle bore diameter... 9380 is larger at 1-3/4" while the 4788 (830cfm) has throttle bore 1-11/16"
Here is the list sheet: http://www.holley.com/data/TechServi...%20Listing.pdf
BTW: You need to back off the primary accelerator pump adjustment... it is all bound up! Loosen the nut on top just to the point where there is no slack between the pump arm and lever. With it adjusted like that I would be surprised if the pump diaphragm isn't torn.
-Chris
Yeah definitely 9380.... 4 corner idle
thanks chris! any advice will help.. i will measure the thottle bores to make sure. i also noticed that pump arm. probably why its leakin..i think my best bet may be to get a rebuild kit,and get it cleaned up. i also noticed it has 78/80 jets in it. plus two pbs. one of which looked pretty nasty. rust etc
Holley rebuild kit p/n 3-648 will have everything you need including detailed instructions. Summit has backordered to 9/7/2009... Might try Jegs or your local auto parts store can order for you.
-Chris
wow! thanks alot! il def look into that. now to clean everything just carb cleaner,and a soft brush?
That's an add on secondary metering plate from another carb.
The base plate was a mod to convert it to a double pumper. This carb is a true vacuum secondary carb.
Where the metering blocks came from is a mystery because this has pieces from all over. To double check the throttle bores, flip it over, remove the base plate and measure the body because the base plate may be off just enough to fool you.
This can be a very workable piece, unfortunately it's been modded to the point you are going to have to tear it down to do a "ground up" to create something to be dependable.
that is a carb that I wouldn't work on and I have fixed a lot of very owner abused carbs--
My usual first step is to identify the carb, stock specs and then go from there ---this one---typical E bay stuff
Can't fault you there Jerry.
I just dug out three virgin carbs out of the core bucket. All three carbs that have that matching 5271/5275 metering block in your rear, are off of 3310 list carbs from the primary side of the carb.
This thing has hodge podge parts but can still be saved.
you guys think its worth a rebuild? or should i just shell out the cash for something new
Totally up to you.
If you don't want deal with correcting this carb, sell it.
If you like the challange, get with it and make this work.
i think my best bet is to bite the bullet and sell it...thanks for all the responses! i have a sbc 383 stroker,with 6inch rods. at 11.4.1 compression,dart iron eagle heads,and a brodix single plane intake. would a 950cfm be about the right size for this motor? or too big
750cfm is about right unless you plan to wind the snot out of it (8000+ rpm!)
for all out racing or driving?
its in a street illegal racecar. so mostly strip,and some street.
CFM = cubes x max rpm / 3456 x VE
use VE=110% for race car 80% for street
this puts you around 850cfm for 383 at 7000rpm
bigger will hurt low tq
yeah that sounds about right. i had a holley 750 with a choke,and couldnt get it to idle for the life of me. im thinkin a quickfuel race 850 will finally do the trick
you know a good shop to send it to for modifying.and cleaning?
anybody have any opnions about buying a new proform mainbody,and metering blocks and going from there? would it be cheaper than a new carb?
joe,
Yes you can add the proform stuff and spen even more money, but seeing that that carb has all sorts of mix and match stuff on it, I would bet that there may be some mods on the inside that you have not seen yet,
sometimes its best to start with a fresher piece. Havin said that you can always take it apart and make sure that there are no stripped threads and welded or modified p/v passages and what not.
Just like the real carb experts on the board say its best to restore it back with the parts it takes and then tune from there than to try to tune a carb that has 850 baseplate, 750 metering block, 650 jets. etc etc,
Been there and did that after spending tons and getting it to run good, or so I believed I borrowed a fresh out o the box carb and dropped my ET, just my .02