I am runnin a 750DP on a 289...no real issues with carb size. It was dialed in on my friends 289, and now he uses an 850. It is all in how you jet and tune it. If you cant jet and tune down your carb, get a smaller one because chances are you are not creating enough vacuum in the venturi to keep the fuel flowing. I run an electric pump with both a gauge and regulator...I want to keep everything set at a constant and know exactly where it actually is. Edelbrock carbs are picky with fuel pressure and can flood out easily when over-pressured...but any carb will. The other thing is dont let someone tell you one brand over another. It is all about what you know how to work with. Your engine has no idea what the name is on the side of the carb...it could care less. It is all in how you tune it, so work with products that you are familiar with. If you are not familiar then get with someone who is so you can learn the ins and outs of your carb. I am no wiz at tuning carbs, but knowing a few things helps more than you can imagine.
CARLOS! Pay attention.....what is wrong with the edelbrock? What is it doing that was so bad. I have had both on the same car, there are advantages to each one but for your application I would sell you the edelbrock....it should work.
Chevy used a Holley 780 carb with vacuum secondaries on there Z/28 302 motors from '67-'69.... These were the same carbs used on the L-78 396/375 motor and the '70 LS-6 454/450 motor... The only difference was the jetting and maybe a power valve change between the 302 and the hp big blocks... List numbers were different also, but still the same carb. One of the tricks that some folks used in the late '60's on the Chevy 302 was to remove the 780 and bolt on a 600 double pumper or a 585 cfm w/vac. sec. Holley from the L-79 327/350 hp motor which pretty much took care of the sluggish low end torque that the Z/28 was famous for with the 780 carb on board..... Bottom line.. You need a smaller carb for that 305!
Yup I know what you mean, I just worked on a 410 FE in a fairlane. That thing would make you cry, and you would stink of raw fuel. Guy was running a biggs 950 carb. We curved the distributor and got some initial timing into it, then worked on the carb. When it was all said and done, it idled well with no smell, drew 12 inches of vacuum (pretty lumpy cam in it), and didn't foul the plugs anymore. It went from 8.90s 1/8th to 7.90s, not bad for that big boat. Plus it drives awsome on the street now The big thing is that no one knows how to tune an engine anymore. Good enough is most people's motto. It sounds like the op needs someone with experience to tune up his ride.
well for one the dam thing hates to start and i have to let it run for like 15 min before i can drive it!!! the needles on the adj in front are all the way out!!! there are times when i come to a stop and it dies or when i go to let down the whole 100hp to the ground it bogs then it goes!!! when i go to take off from a light the car starts to bog alittle its weird!!! its almost like it doesnt send out enough fuel!! when i got the carb it was rebuilt so idk what the hell is wrong with it..... so now mr donny tell me what i should do??
When you have too big of a carb, fuel atomization is not good, combine that with low vacuum and late timing and you can light the exhaust on the way out - cool if you have flamethrower tips I guess . . .
You need a tune up. plain and simple. Is your ignition system up to par? Plugs wires cap rotor coil? Was this 305 at one time Fuel Injected? Is the ignition timing set right? Are you sure you don't have any vacuum leaks? Are you sure the intake manifold mating surfaces don't have any vacuum leaks? Are you sure your brake booster if you have one isn't causing any vacuum leaks... you see where I am going with this?! Sounds like a vacuum leak if it has to idle with the idle screws all the way out... ****ing way too much air in somewhere, and you need to compensate with rich idle mixture. Maybe your pcv valve is gone, like no parts in it, causing a huge vacuum leak (i've seen it before). How about the vac*** modulator on the trans is that ruptured... most likely you would be blowing oils smoke, but maybe it's unhooked... how is the vacuum advance canister, is that bad? How's the accelerator pump? That could be the issue with the bog on acceleration, combined with say a vacuum leak. Like I said you need a tune up. Find someone in your area that is GOOD with this stuff, not just someone's buddy... Look for someone with a fast proven car old school car that does their own work, then maybe you'll find someone who knows what they are doing... or learn it yourself. A new carb isn't going to help you from what I've been reading
Wow, Carlos. Listen to Zman and the others who are telling you the truth. The Edelbrock is a fine carb and the right size for your engine. You don't have to fight it, just fix it right. If you don't want to fix it, send it to me and I bet I can make it work. You just won't get it back... The Edelbrock carb should be fine for what you are doing. Carburetors are not rocket science, but they require attention to detail and a good process of elimination to solve your problems. 1. A quality fuel regulator is a MUST for an Edelbrock carb. Without one, you are just chasing your tail. Don't get a ****py Spectre from Autozone, get a high quality regulator and set your fuel pressure right. I seem to remember 2-3 pounds, but I am not sure. 2. Go to the Edelbrock website and find out which needles and seat you need to start with a baseline, factory setting. Since you said it was rebuilt before, I can guarantee it is not jetted for your engine. Get a baseline setting, according to Edelbrock, and start troubleshooting from there. 3. Use the charts and diagrams and instructions and fine tune the Edelbrock until it works perfectly. It will run, but it won't run well at factory settings. You are better off in the long run to take the time to set it right, according to Edelbrock's directions. 4. Clean clean clean. Dirt is your enemy. A single spec in the jets will cause you grief. Keep it clean and install a good fuel filter before the carb. Edelbrocks are not Holleys. You can't transfer your Holley knowledge to them. That being said, a carb is just a fuel/air mixer and there's not a lot to them. An idle circuit, acceleration fuel boost, driving mixture, and wide open throttle. One works just as good as another and swapping out carbs without regard to fixing what you have and getting it to run right is just silly and wasteful. If you just want to throw money around, I can have you send it to me...
Mileage is a measure of efficiency. A stock 305 is max 200 hp no matter what carb you put on. Tune for the street, you'll be happier with the result.
On my 1978 GMC shop truck with a 305 I have an Edelbrock 500cfm, that is about as big as you would want to go.
well to answer your questions!!! yes all that has been checked!!!! and i may not know everything but iam well aware of all the issues that you stated!!! and i do have buddys that are well aware of what they are doin!!! at one point I did have a va*** leak coming from one of the intake bolts so i went ahead and got a new intake!!! the plugs cap and rotor is all brand new!!!! wires are new!! i dont have a booster!!! pcv valves are over rated and i ditched mine!!! dist is new!!! if the va*** line goin to the trans mod was bad it wouldnt shift right!!! and i have checked all my va***s and they all seem to be fine!!! my carb has been rebuilt and that hasnt fixed it!!!! money i dont have to throw around but for 50 bucks that i spent on a brand new carb, doesnt mean that iam rolling in the dough!!! so that means that maybe a new carb will fix my problem!!! ohhh yeah timing is also set right!!!! and no my motor was not a efi motor!!! so that being said looks like a carb might be my issue!!! trust me if i needed a tune up i wouldnt be on here asking for advice!!!
Re: "pcv valves are over rated and i ditched mine!!!" Hmmmm,,,, You need to vent crankcase vapors,, its not overrated,
Obviously not if you were not told to put on a fuel regulator. It really sounds like you need to download the actual instructions from Edelbrock and learn. Learn how to do it yourself. And correctly not just turning screws hoping to get lucky. Wow, really? Maybe you can't learn. It sounds like you really don't want to fix anything, you want the easy bolt on solution. Hate to tell you it does not exist.
well to justify the pcv comment i took it off because when i had it on i was getting allot of blow by oil coming out of the exhust..... so i took it off and put a breather in its place and it fixed the smoke coming out of the exhaust!
Waukegan as in waukegan Illinois, as in not at sea level, as in the stock jets and metering rods on an edelbrock carb are set for sea level so you are needing to rejet to 8% smaller jets because you have less oxygen and it affects your air fuel mixture ratio, did you get the owners manual for the brock? Do you have a jet kit? You do realize that in the old days before Nintendo and X box that we had a choke on a car that was mechanical, so the poor thing has to get up to temperature before you take it jump on it, it may take 5 minutes or so for the carb to mechanically adjust it's air flow mixture to operate properly. Now days you jump in the thing in January when it's 4 outside and off you go because you have a nintendo in there applying life support for you.
Take it easy guys, Carlos is a good guy, he's just ***ually frustrated and really likes to use exclamation points!!!!. The reason the PCV was ****ing oil was because you need a breather on the OTHER valve cover. I can honestly say I have never heard of needing regulator with an edelbrock carb. We have put a lot of them on and never really had a problem. You just have a stock style fuel pump right? Has anyone adjusted the choke? It shouldn't have to run for 15 minutes before you can drive, I don't care how cold it is. It shouldn't run at all with the both mixture screws all the way out unless it is really screwed up inside. Jetting may or may not be right but i have never seen an edelbrock that wasn't pretty damn good right out of the box, that's why we run em on mild motors. Who rebuilt it? Where is timing set at? For anyone to fix a driveability issue over an internet forum without seeing the car or knowing the entire history of what has or has not been done would be pretty damn impressive. I don't believe for a second that there is one answer to the problem but i know what the answer isn't in this case......a 750 Holley. Give me a call or swing by the shop tomorrow morning and we'll cover some basics and see if we can't get you going in the right direction. If I fix it you can mow my gr*** Donny
Waukegan is approximately 669 feet above sea level. The elevation at Laramie Wy is 7200 ft, the difference between here and there on my Holley was 2 jet sizes. While you theory is correct I don't find it applicable in this situation. I didn't know you could use a nintendo to run a car. Is nintendo slang for computer in Chicago? Are you typing this at a nintendo? Why do you hate nintendo? Do I win the prize for using nintendo the most in a paragraph?
***ually frustrated??? really??? hahahaha ummm no i cant say that the choke has been adjusted. carb was rebuilt by some old timer here at work he use to rebuild carbs back in the day, so he says... I have seen plenty of cars without regulators and they run just fine!!!! The car ran great when I first Started driving it back in may. but then after that i havent been able to get it right... hahahah you can all adan iam sure he can cut your gr***..... iam no gr*** cutting mexican iam just a mexican!!! hahaha
It recommends the use of one in the instructions that I have sitting here on my desk. I think you can take their word, as they made the carb. Stock, or stock style fuel pump, or not, if you have no fuel pressure gauge, you are just guessing about fuel pressure. For these carbs, it should never go over 5.5 psi. I have had best results at 5 psi. I have never installed an Edelbrock carb without a regulator, after having over 30 customers complain of a carburetor that couldn't be tuned. Of the 30, three required additional work (beyond setting the float level) other than simple tuning. Lucky is is not a business strategy or a survival strategy (or a tuning technique).
That's cool. I am not trying to start a debate about the regulator, I just never have heard it. the instructions that I have are dated 1996 and I just scanned them quick and didn't see it in there......I guess there is an update and I should keep the next set. Does it give a reason why it wants the regulator? I can't be clear enough here I am not arguing, just wanting to understand. I know what you mean, pressure out of the pump can vary greatly from pump to pump and manufacturer to manufacturer so I understand the need to regulate and ensure proper pressure. But again I have never had a problem related to pressure with an edelbrock, 2G's on a tripower, absolutely. So it ran great in May and then.....you worked on it? I am guessing dirt in the bowl, stock tank right? Old dude rebuilt and it got better or worse or the same? Pull the top off the carb and see if there is **** in there. That said, I am not a carb expert. If they need anything more than idle and choke set we send them to the dyno shop, it's cheaper and quicker to let the guy that works on carbs all day do his thing than for us to muddle through it. I guess that's my disclaimer......I'm a dummy when it comes to the fine tuning of a carburetor.
I had a 750 dbl pumper on a 350 cid and I was camming and it was okay. For a stock 305 cid I'd run a 550-650 depending on what you can find. Maybe your Edelbrock carb is messed up, manual or electric choke?
They don't spell it out, but over about 5 1/2 lbs of pressure and they run like ****. Push past the needle and seat etc. I usually run them around 4 1/2 personally. I agree about checking for dirt since it ran fine at one point. Even if you don't want to put a regulator on there at least verify the fuel pressure.
hahah then i worked on it?? nice.... nope brand new 66 mustang gas tank in the trunk. after he rebuilt it, it ran great but after a while I started to have trouble with it. Ill pull that top off and see if there is any dirt in there tonight when i get home from work. and i guess if a regulator is gonna fix the issue that iam gonna have to get one.. you guys have them in stock donny???
Taken from the Edelbrock tech center; optimum pressure is 5.5 psi. http://www.edelbrock.com/automotive_new/misc/tech_center/install/carb_faq.shtml
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