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What carburettor is this...?

2K views 16 replies 9 participants last post by  The Z'eer 
#1 ·
I do apologise for asking what may seem a most obvious question. Sadly to me who is very new to this style of motoring it is not.

I was advised by the previous owner who fitted it that a 750 Double Pumper it is (no invoice), however I have heard it could be a vac sec??







Could anyone confirm exactly what it is? I need to order a gasket kit ASAP as fuel appears to be leaking on to the manifold below.

Many thanks :)
 
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#3 ·
To be a little more specific, the round housing hanging off the side of the carb in the center of this photo is the vacuum actuator that operates the secondary throttle plates, which is what makes it a "vacuum secondary" carb. There is no mechanical connection from the accelerator pedal to the secondary throttle plates. That vacuum actuator opens the secondaries in response to engine airflow need, not your right foot.

 
#5 ·
Looking straight at your carb from the front of the engine bay on the right hand side or what would be called the driver side of your carb you should have a set of numbers that will be something like 1850-8 (the number after the dash will vary) or 80457-5 or 3310-8 or 804508-5 .

I would bet that it is a 3310 which is a 750 vacuum secondary with manual choke and the 804508 model comes with an electric choke. The 1850 and 804507 model carbs are 600cfm vacuum secondary with a manual or electric choke. It could also be a 650 cfm vacuum secondary but I don't know the number right off hand but the four most popular models that holley sells for basic street carbs are the 750cfm 3310 manual choke and 804508 electric choke and the 600cfm 1850 manual choke and 804507 electric choke.

The numbers below it would be for example like 1245 which would mean it was made on the 124th day of year ending in 5 such as 85 or 95 or 05 etc. The fuel bowls and metering blocks are able to be swapped from one model to another so unless that is the original parts with that carb you can tell what it is with the numbers.
 
#6 ·
You'll need that info that eric pointed out to buy a new base plate to replace the one you have that has that cracked mount flange on the passenger side back.
Or since you need a kit and a baseplate you might as well get a new carb because you'll undoubtabely be having to pay some mechanic to fix it for you.
 
#7 · (Edited)
Below is a rebuild kit that would have everything you would need to do a whole rebuild and it also comes with more parts then the holley brand kits and is still the same quality. Also if you don't know much about holley carbs you can buy books from amazon that shows you a whole lot of photos on how to rebuild a holley carb and the only thing you need is some basic hand tools and nothing fancy and it is pretty easy once you familiarize your self with one. If you need a new base plate then holley part 112-112 is for the 1850 and 80457 models and if its a 3310 or 804508 which is the 750cfm you would need 112-117 base plate.

the 600cfm base plate has 1 9/16 butterfly size and the 750 would be 1 11/16 and is pretty to replace them and just unhooking the rear vacuum pod lever and six screws and then it pops right off and if you were to get the book it shows you everything top to bottom and also its in color so you can truly see everything and if you had any questions I would be happy to help in anyway I could as that is why I learned this stuff to know how to do it and also help others.


https://www.amazon.com/Holley-Carbu...1497028794&sr=1-1&keywords=holley+carburetors

https://www.summitracing.com/parts/qft-3-200qft
 
#9 ·
Eric, that's great! :) once again, thank you very much for being so helpful. I must admit I am a little reserved about dismantling a carburretor. This isn't something I've tackled before and I do believe they're pretty complicated? This could be quite a leap for me.
 
#10 ·
The 3310 lives on

This carb is the aluminum version of the 3310 that has been around since forever, ive run both the old and new versions and i will say one thing they are reliable. fuel efficient and tune-able, not bad, comparable to a double pumper when the secondary's are dialed in, sure why not.
 
#11 ·
No problem on wanting to help. I was there over 8 years back and did not know anything about a holley except turning the screw to set the main idle and that was it. After many years of tuning and book reading and thanks to a lot of very helpful generals on here and looking up stuff I have learned quite a bit on those carbs and the 3310 model is an icon when it comes to holley carbs and has been around forever and is one of there top best sellers along with the 600 vacuum secondary ones.

Any other questions just let me know as I would be glad to help you out any way I can.
 
#12 · (Edited)
I think the 12 after the 3310 indicates whether it was made for GM, Ford, or Chrysler throttle linkage parts... This carb. must have a good seal to the intake manifold or air leakage in will lower vacuum and cause the Power Valve to be open and dumping excessive fuel into the engine at all times...

BTW, it's a great, simple carb... good to 500+ HP... I love them...

Youtube has all kinds of info and instruction videos on them... (not everything is accurate) ... When the vacuum secondaries open/what RPMs level is adjustable... The main jets can be changed to suit your engine size...
 
#13 ·
The dash number after the model number does not have anything to do on what engine it came on but is just the update that holley does on there carbs over time as for instance I have several holley 650 double pumpers and the number is 4777-3 and my newer ones have 4777-7 and the same thing with my 600 holley models 80457-6 and up. When holley changes slightly some things on the fuel curve or just something minor they then just put a higher number in the dash.
 
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