I've already gotten so much help here I hate to ask for more but I don't really know a thing about carbs. Currently I have a 750CFM, vacuum secondary Holley 4 barrel on my 350 (bought it this way, plan on getting a 500-600 later on because the 750 is too much) and I have no idea why it's not working. The car wouldn't start so I looked under the hood, pumped the accelerator and the gas just poured out the front of the carb, so I let it sit for a few days, got back to it and no gas leaked out when pumping the gas but it still wasn't getting gas so I directly put gas in the carb and it started right up. I figured it'd die once it burnt up the gas I put in but it ran just fine for 30min. Once I parked it though the carb started leaking again,not as much, but enough to make me worry. Considering what I know right now any ideas would be appreciated.

It kinda sounds like it could be 1 of 2 things. First is the float level set correctly? With the car sitting level and pressure supplied to the carb the fuel should be just at the bottom of the site window on the side of the bowls. If the float is set to high fuel will run out the vent tubes. Second if that checks out it could be a stuck needle valve on the front float bowl as that will also do the same thing. The fact that it ran fine for a 1/2 hr is what is so strange. If the floats where high it would have been shooting fuel. So that's what makes me think it could be a bad needle and seat that was just stuck open.

Can you tell where the gas is leaking from? It could be the accelerator pump diaphragm.

Can you tell where the gas is leaking from? It could be the accelerator pump diaphragm. When it was leaking it went all over the manifold and looked to be from the main gasket, but it was only in the front not anywhere else. And thanks HarleyD67, I'll see if I can figure out how to check if the needle valve or floats are the issue.

Ditch the Holley and get yourself a Q-Jet. With the right mods, the Q-Jet will out perform the Holley EVERYDAY!!! With a spreadbore(Q-Jet), you get the best of both worlds. Small primaries make for great mileage and AWESOME throttle response and the large secondaries make for OUTSTANDING power. With a Q-Jet you can run an 800cfm carb on any engine and it won't be TOO MUCH. The carb will only give the engine what it can handle. I switched from an Edelbrock Thunder 650 to a modified 800cfm Q-Jet and I will NEVER go back. To anything. My carb/engine runs like fuel injection. I have a ROCK SOLID, and I mean ROCK SOLID idle @ 700rpm in drive and 900rpm in park/neutral. She fires like a champ and has more than enough power spare. You should seriously think about switching to a Q-Jet.

I suspect a leaky primary throttle shaft!.....If severe, the engine will not run properly or will not run at all!.....Check for fuel leaking out the ends of the throttle shaft and a puddle of fuel collecting on the intake manifold.

It could just be time for a rebuild. If it has set for a long period of time the gaskets could be shot. The diaphragm in the accelerator pump could be cracked or torn. If so, the leak would be in the front and under the carb body, above the base plate.
Also, don't feel bad about coming here asking for help. Everybody here has probably learned things and taught things on this site. Nobody can ever know everything about everything.

Yeah, I really want to take the holley off, it makes staring the car a nightmare since it's not a daily driver. I looked up the Q-jets and I'd love to put one on, but since I'm only 17 and still living at home I have to do what my dad wants, I think he plans to put an edelbrock 500 on it. But when I'm on my own I'm definitely going to make some changes. And thanks Badbird and deerhunter, any ideas are helpful at this point, I'm still pretty much a novice when it comes to anything mechanical, which is why I hate asking for help. I see some guys on this site and others rebuild 67's from the ground up so I'm a little shy to ask for help with something like a carb.

At least you are trying to learn. I personally would go with either the 650 or 670 Street Avenger, both Holleys, before I went with another Edlebrock. You already have the square bore intake. If you do decide to go Quadrajet, you will either need to change the intake manifold to spreadbore or use the adapter. With the adapter you could possibly have clearance issues. I have never used the adapter but from what I have read on here, I won't be buying one. Try a search on here for information on all 3 brands I just mentioned and I would be willing to bet you will be busy for hours!

Don't worry everyone needs to ask for help every now and again. Remember the only real dumb question is the one not asked and the one just answered.:clonk:

Get a basic Holley rebuild kit. $20.00-25.00 and they come with pretty good instructions and pictures. The biggest thing though would be to check the carb for damage first. Take it off the motor and check the throttle shafts for excessive play and check the rest of the card for loose or missing hardware or cracks. For a first time to tear down clean and rebuild a Holley your talking 2-3 hrs max. For someone who's mechanically inclined and good reading technical drawings 1/2 that. So go ahead and give it a try. Worst case it still doesn't work right and it only cost you or your dad $20-30 bucks and an afternoon together bonding. ;)

I would use a 600cfm Edelbrock, not a 500cfm. Usually 500cfm's are used for dual carb setups. Almost any engine can handle 600cfm.

I would be willing to renew your Holley carb free of charge, as long as the throttle plate, throttle shafts and floats are good!.....Mosy likely, you have the list #3310, which are very easy to renew!.....Just send me the carb, along with a renew kit!....PM me, if interested!

Thanks Badbird thats so nice of you to offer, but I still have to go through my dad for the ok on anything I plan or he gets upset. I'd like to put a Q-jet on, like the one you mentioned, 67CamaroRS/SS, but right now we have 2 Edelbrock's, the 500 & a 650, laying around so I'm going to be stuck with whichever one of those my dad decides to put on. For now I'm just going to get the Holley back in working condition, I can't stand having a car just sit there and rot.

Thanks Badbird thats so nice of you to offer, but I still have to go through my dad for the ok on anything I plan or he gets upset. I'd like to put a Q-jet on, like the one you mentioned, 67CamaroRS/SS, but right now we have 2 Edelbrock's, the 500 & a 650, laying around so I'm going to be stuck with whichever one of those my dad decides to put on. For now I'm just going to get the Holley back in working condition, I can't stand having a car just sit there and rot.
try to talk your dad into puting the 650 on there.it will run better.you will have more power and still get good milege.a 500 is to small for a 350 motor.it will run but a little small.tell dad to trust you on this one.lol:hurray:

go to this link
it got all your questions answered
http://www.bob2000.com/carb.htm

I would be willing to renew your Holley carb free of charge, as long as the throttle plate, throttle shafts and floats are good!.....Mosy likely, you have the list #3310, which are very easy to renew!.....Just send me the carb, along with a renew kit!....PM me, if interested!

That is a very generous offer you made there, Badbird! People like you make the world a lot easier to deal with!

That is a very generous offer you made there, Badbird! People like you make the world a lot easier to deal with!


Thanks!:thumbsup:....I'm not working, bored, nothing to do and need something to do to keep my sanity!:wacko:

Sadly, I know exactly how you feel.

I think the lyrics from this Styx tune fits me perfectly right about now!....."Too much time on my hands", "I got nothing to do and all day to do it" :yes::mad:

http://www.styxnet.com/styxlyrics/tmtomh.htm

It's strange how, when you have the time you have no money and when you have the money, you have no time.

I suspect a leaky primary throttle shaft!.....

I ran a used holley 600 for a couple weeks while waiting for some carb parts to show up for my edelbrock that I messed up while rebuilding (doh!). the holley had a little leak around the throttle shaft just like was mentioned. sounds like it may be a common problem (i don't know holleys). also, do you have a manual or electric choke on the holley, and is the choke and fast idle working properly? might explain the hard starting problems. could be your fuel bowls are leaking while the car sits and it takes a while to get the carb filled up again when you go to start it.