Holley 3310 750cfm Rebuild

[C20-67_N_MO]

Bought an engine that has this carburator and it does not idle very well.

Tried playing around with the acc. pump adjustment arm and seemed to help a little. But the engine keeps "falling on it's face" and I am thinking it is staving for fuel and the vacuum secondaries are not kicking in or working at all.

So my question is how difficult is it to go out and buy a rebuild kit and install it and get it working correctly? Or should it be sent off to a professional that knows how to properly set it up and rebuild the carb for the engine?

Let me know what my options are as new carbs are too expensive these days!

Thanks!

[Captainfab]

If he doesn't chime in here, send a PM to prostreetC10. He's the Holley expert on the forum.

[prostreetC-10]

Scott,

Hey silly......you could have just called me on this one too! I don't usually charge for info. )

We can leave the secondaries out of this for now. They have nothing to do with what you are talking about in the beginning. If you are talking about that carb that came on the 406, there could be a bunch of things going on. When you have a carb that you really can't say if it's been out of service for a year or 20 years, you almost HAVE to start from scratch. When those accel diaphragms dry out really good, you can still work the throttle but the pump will only compress a bit and the rest of the stroke will be absorbed by the spring in the pump arm. Problem is that the butterflies will still open so you run into a bad lean spots.....AKA.....stumble......fall on face.

As far as the idle problem, same thing with no prior knowledge. If the motor tends to "shake" at idle, that's usually a lean condition. Not getting enough curb idle fuel. Are you trying to run it on that 406? I think I need to clarify something I told you on the phone. When I said that 3310 would be better than that motley 600 you sent me pictures of, that was true but it's probably not the best carb for that setup. The downside to that particular carb is that it has the straight leg boosters. I"m guessing with the 12:1 comp and the other things we talked about, your buddy is really going to want a carb with down leg boosters. That thing will probably spin pretty good and the straight leg boosters are not ideal for that RPM. I love the 3310 on my 454 but she seldom sees over 5K rpms. Got a feeling that 406 will go well past that. The 3310 will surely fall off in those upper rpms. It's all about physics. He may just need his double pumper after all. lol

Give me another call if you want more info.

[C20-67_N_MO]

Justin,

Yeah it's sitting on the 406.

The problem is right now he is borrowing that carb as he wants to run a double pumper as he hates the vacuum secondary carbs. And this one is a fine example of that. lol

We are both in the same boat as not being able to afford a new carburator at this time and he just wanted to try this carb. He has to replace the camshaft as his buddy adjusted the valves too tight and flatten the lobes. YIKES!

But what I did find online is they say these 3310s can be rebuilt to make 25-50 more ponies. And yes it will cost some bucks to make this happen. One is to replace the main carb body with the ProComp main body kit. Will try to find that article on my work PC and post the link.

So back to my orginal post, can an average Joe like myself successfully rebuild a carburator like this and have good results!

Have a good weekend everyone.

[prostreetC-10]

I believe there are two terms here we have to look at. One is "rebuild" and one is "kit". For a lot of years I was "kitting" carbs. In other words, I was basically swapping out the gaskets but didn't understand how to truly setup the carb once that was done. I also didn't know how to identify problems the carb I was kitting had. If you have a carb with issues other than just the gaskets, when you install the rebuild kit, the problems will still be there. Properly setting up the carb and getting the initial "bench" settings correct are very important.

Now for that dirty little word you said "PROCOMP". This is that line of aftermarket carb bolt ons that we talked about where you can get new bases, blocks, and bodies in the $60 range. Don't we ALWAYS get what we pay for? This is no different. Horrible workmanship and materials here. You will be lucky if you can even get your bowls and base to be able to bolt on to the new main body. The holes are usually not squared and you will have to leave everything loose and hopefully "catch" all the threads at the same time so they can be snugged down. Forget about the bores in the main body lining up with the throttle bores in the base. Not going to happen. Junk, Junk, Junk.......

Now as far as PROFORM goes......much better quality but still no where near Holley specs. Who ever came up with the "25 to 50 HP gains with a simple main body swap" should be hung up by their gonads!!!! Not going to happen period. You can pick up that kind of HP by taking similar specs and transferring them to a roller cam from a flat tappet but not a stinken main body swap. There are actual cases where the main body swap LOST HP on a dyno. Usually 2, 3, 4, 5 or so is the expected gains. The only was you will see more than that is if the original main body actually had a problem before the swap. The main body swap will also benefit a drag motor far more than a street application. The gains are just not there. One of the best things you can do to a street carb for increased performance is to simply mill the choke off. It is proven that by leaving that little piece of choke tower in between the primary and secondary venturies actually helps the signal to the primarys which is great for street applications where your carb is spending most of it's time.

I really feel that if funds are an issue right now, rebuild the 3310 you have right now and completely forget the main body swap. You will be disappointed. Take that money and save up for a fine carb from HP Carburetors AKA ProstreetC-10 or buy the right one off craigslist and rebuild it too. I can also supply you with some good tips on setting up the carb after the kit has been installed. Just be careful putting too much money into the 3310 when it's not the best carb for the application.

[C20-67_N_MO]

Sorry it was a type-o, It's called the Proform main body kit not ProComp.

Proform CARB UPGRADE KIT 3310
Part Number: 778-67101CK

$289 from Jegs

[C20-67_N_MO]

Yeah I will get a rebuild kit but like you said if the problem is still there and after replacing gaskets only then it's not really solving any problems.

What about cleaners.

Should I get a can of that stuff or what?

Once I have the carburator apart then should everything be spray with this off the shelf can of cleaner?

Thanks for all your help.

[prostreetC-10]

Do me a favor Scott....send me some good pics like you did of the 600. Let me at least look it over good to make sure I don't spot something obviously wrong with it like I did the other carb. Also, try and read any numbers that are on the top of the metering block (assuming there is only a primary).

You said that money is a bit of a concern. I can't imagine you spending $289 on that kit for that carb. Do you have any idea what this motor is going to spin to? For that kind of money you can get a good used double pumper ready to go. The bulk of that cost is for the main body which looks pretty but you can forget about those 25-50 hp gains. You don't need the billet plate in the back. You need a rear block for far less cost. Just rebuild the carb as is and see where the project takes you guys and then buy the correct carb for the intended use.

As for carb cleaners, I prefer to both soak and spray my carbs. The stuff in the can is actually stronger than the chemdips. I like to soak my parts with Berryman's to really loosen the crud up and then use the can cleaner to wash the pooh away. Careful of soaking time though. It can really remove your finish. Soaking time depends on just how dirty the carb is.

One downside to the rebuild kits is that most of them won't come with a new vacuum diaphragm. I believe the best kit out for what you are going to do is the Barry Grant kit. This is the kit and this is the guy if you use eBay at all. Kit can't be beat.

http://cgi.ebay.com/ebaymotors/BARRY...item3ef1350512

I used to buy these kits before I started getting my supplies in bulk.

[C20-67_N_MO]

I'll see what I can do about getting you some pictures. This carb looks brand new on the outside.

But it does not perform as good as it looks.

Thanks.

Will email you Sunday sometime.

[prostreetC-10]

If the carb looks that nice, it's probably not that old or just in good condition so it sounds like a good candidate for a rebuild and a good starter for a newby.

[C20-67_N_MO]

3310-2

you told me it is old.

might have been rebuilt.

I would love to try to rebuild it if not your getting a work project in the mail soon!

[prostreetC-10]

A 3310-2 IS an old carb. Should still have the check ball fuel bowls and the brass floats. If it's clean it doesn't really matter how old it is. They didn't and haven't made too many changes to the 3310's.

I'm doing an experiment for you because I'm bore, I have a little time and I have the parts. Going to build your proform 750 HP vacuum carb you talked about earlier. I'm also going to build an 1850 600 vac into a 4150 and use a 750 block in the front and a 650 DP block in the back with center hung floats. Why is this crazy fool mixing up all these blocks? Because you can!

My fresh 454 hauling truck currently has a 3310 on it now. Going to try the proform 750 HP and the modified 600 to see which one the motor likes best. Notice I said the motor and not me? Should be interesting. Here is the truck and the start of the 750 hp.

[prostreetC-10]

Well Scott I got 'er together but ran out of time to try it out. Turned out pretty good for all used parts I had laying around.

[C20-67_N_MO]

Yeah I made a trip to wine country today so I was not able to get to my friend's house and take pictures of the carb.

WOW!

Yours turn out looking nice. And should preform just as well.

Dang! That carburator of yours looks brand freaking new!!

Keep me updated on how the engine likes or dislikes it.

[prostreetC-10]

We will see. One thing that bugs me, which is another sign of a Holley knock-off, is how the boosters sit slightly tilted back. You can see it better in the pic of just the main body and the base. They should be sitting more squared to the venturi. I'm acutally more excited to try out my little 600 than I am this one. Won't be till later in the week. gunna rain the next two days then sunshine. That ole truck will flat ignite the tires in the wet. Stay tuned.......

[C20-67_N_MO]

Hey!!

Is it worth my time to rebuild this 750cfm or should Ijust send it off to you? Or are you wanting me to send you pictures of it before we do anything at this point?

Thanks man you rock!

[prostreetC-10]

I do think it's worth your time to rebuild it. That's what this forum is about. Helping/teaching people to do it themselves!!!!

Problem with me doing it is that you have shipping both ways and I can only do bench settings. Granted, they are close but you will still have to dial it in for THAT motor. 3310s are also pretty simple carbs. You are not trying to sync a 4 corner idle so that makes it a little easier and if you just follow the instructions that will come with the kit, you should be okay. There is also a ton of info on how to dial in a Holley both here and online. If you rebuild it and something goes horribly wrong, you are only out the cost of the kit and the time spent.

Here is my little Frankenstein 600. Looks a little different than the 1850 I started with. Cool because it will look like any other double pumper when the air cleaner is on. I'm running a 750 block in the front and a 650 DP in the back. It's not all shiny and new but that never made a Holley run better anyway.

[C20-67_N_MO]

No offense but it looks like a vacuum secondary carb.

I'll gladly give it a shot at rebuilding the carb with a kit but not sure what all needs to be adjusted other than the accerator pump arm and the two air/fuel mixture screws.

[prostreetC-10]

Originally Posted by C20-67_N_MO

No offense but it looks like a vacuum secondary carb.

...but if you put a drop center air cleaner, which is all I run, you don't see the vac housing.....anyway. lol

In general, as long as the carb has the OE stuff on it, that's about it. You want to make sure the throttle blades are not goofed up. Back should be closed with just a tad turned in on the set screw. Main thing is to make sure all of the passages (emulsion holes, air bleeds...etc) are completely clean and open. Check for proper jetting from factory. Front should be 72 and the rear plate should have an upside down 21 stamped in it. From there just follow the instructions in the kit. Let us know how it goes.

[C20-67_N_MO]

Any updates on how your engine runs with this carburator?

Still have not gotten over to get the carb and take pictures but will do so this weekend.

I need to PM you on another matter I am thinking about doing. :evil:

[prostreetC-10]

Yeah.....lovely update: I have the flu or something close to death! WTH??? It's only Oct. Why am I so sick? Anyway........will be a bit for sure. No problem on the PM. I do have moments of clarity. lol

[prostreetC-10]

Well I finally got around to testing the 750 HP vac I built. Man was I impressed. This thing flat rips. I wasn't sure how the 454 would react given it was in a 5,500 lbs truck with an auto and stock converter. There was ZERO hesitation all the way through the fuel curve. I would LOVE to see how this would work on a decent motor in a 3,200 car. Granted, this was built by the fine people at HP Carburetors.

The 600 didn't fair as well. The metering block I used has too big of an idle feed restrictor for the stock, fixed idle air bleed the main body had. It causes the idle mix to be way too rich for what the needles can trim out. I don't want to alter the body so I will work up another blocks with a smaller restriction.

[C20-67_N_MO]

WOW!

Which mine was the HP model!!

That thing looks like it can flow like a mother!

Okay back to earth, not sure if it's my friend's mental attitude towards Vacuum Secondaries or it is really true, but he swears it has a hesistion. I know some of these things can be adjusted just not sure how.

Any thoughts Mr. Holley?

[prostreetC-10]

WHAT has a hesitation? Vacuum and DPs can both have a hesitation but you will feel more with the DP in many cases. A correctly adjusted vac carb should never "feel" like it's kicking in. Maybe just a bit more noise. If you are running a quick change kit, you can have the wrong spring and get a hesitation.

ANY carb that needs rebuilt, on wrong application and other things can hesitate, buck, snort and what not.

Tell me more.....

[C20-67_N_MO]

I wish I could tell you more.

As all I am is a passenger and not the one behind the wheel.

And still have this Quickfuel rebuild kit sitting in my house and not on my carb that he is borrowing! So all I can do can is go by what he is telling me.

BELEIVE ME! At this point I am not worried about it! Just posting what he has been saying about my 3310 on HIS car and MY engine. Sorry just a rant until he starts making payments back to me. AURGH!

Yeah if you still have my email addy send pics of that carb you mentioned via PM.

Thanks Justin.