I am wondering if I can put a Holley Double Pumper on a 305 4bbl car its not the high output model atleast I think its not, the holley was used on a 400 big block olds motor i think the motor was from 69 not the original to my moms 1975 esprit. (Damn I want that motor) She had to take it off since whenever she would stop it would stall so she had to hold the pedal down slightly at stops so it wouldn't stall also she was saying that sometimes the motor would almost light on fire.... But she told me that was because it wasn't hooked up properly....

 

You can't bolt it to a factory 305 intake manifold.

A carb that fed a 400 is probably going to be too big for a 305. Besides, why are you thinking about using the Holley on a 305? The list of performance restrictions for a factory 305 go, in order: Exhaust, air cleaner, cam, intake valves, head ports, intake manifold.

Notice the absence of "carburetor"?

 

If youre running an automatic trans id stay away from a double pumper they dont respond to sudden accelleration very well they are better suited for a manual trans car. A vaccum secondary carb is better for an automatic. Even then i wouldnt go much bigger than a 650 cfm carb a 600 cfm would probably be even better yet.

 

could I bolt it to a 350 motor its not a stock motor I think it came from a truck or something I believe its a 4 bolt main.

 

No, a vacuum secondary carb is not better for an automatic. Better for a tow vehicle, maybe, but the double pumper is the superior performance choice.

 

Depends upon what intake manifold is used.

 

Hmm I see I was thinking of maybe a high rise aluminium intake but I am not sure everything will fit and the hood will be able to close, I really don't want to have to go through the effort of putting on a hood scoop because I like the way my factory hood looks.

 

Just because its a Holley, doesn't mean it will help performance, the wrong carb in the wrong application will hurt performance and economy.
Also depending on the carb or the source it came from, it could be simply a factory Holley unit, which is no more performance oriented than your quadrajet. In fact damn good results have been netted from Rochester's there is a whole cult following that test and tune them with good results. do some googling and see for your self.
and as was listed above, start with mods that will actually benefit your 305, I've seen some pretty stout little 305's making respectable power. Its all in good planning and choosing the right parts for the application.

 

it would stall at lights and catch fire because the carb was too big. the car was running pig rich. so if it was too big for a 400, it will be too big for your stock 305.

 

No No No No... I am not putting it on a 305 anymore I will be putting it on a 350! not a 305 I was planning on buying a 87 camaro with a 305 it was to much and to damn rusty, I bought a T/A with all options for 1750, and the rusty 305 was 1500 with no options....

The motor in the T/A is a 350 I think it came out of a truck possibly out of another T/A or Camaro.. I am not sure.

 

Another reason the 400 was running terribly it wasn't set up properly. the intake manifold wasn't large enough to support it and the carb needed to be rebuilt
.

 

The double pumper is the right choice if you do alot of racing but on the street the vaccum secondary is better I'm not saying that double pumpers are bad or junk but that they have their place and on the street their not practical. I wasnt trying to start a war about who's right and who's wrong. I'm just trying to help the guy out so he don't make some mistake that he regrets later. Every carb has their UPS and Downs it doesn't matter what make or model of carb you get just do some research on your application.

 

There is absolutely nothing impractical about a double pumper for the street. What type the secondaries are is irrelevant when you're only using the primaries. However, the downsides of the vacuum secondaries are sufficient to say go with a double pumper on an engine that is in any way performance-oriented.

As you yourself said, do your research for your application - doing so will lead you to properly size the double pumper so the problems you think they have will be avoided.

Having said all that: Travis, any reason not to use a q-jet?

 

No I might use a q-jet i'm not sure, the car is just for cruising and spring and summer fun, I don't think it will see the winter unless I can't borrow my parents truck for the winter, it might be driven on the track down in Osyooso or Oliver, I heard there is a drag strip somewhere around there.

 

Then why didn't every car from the 70s and 80s come with a double pumper. Oh and isn't a qjet a vaccum secondary carb ??

 

Edelbrock Performer RPM is all the intake you will need.

 

intake manifold being too small has nothing to do with a rich mixture, if anything, it actually helped on the street.

what size is the carb?

what are the rest of the specs on the engine as well. no one can really help if they dont know; compression, cam specs, heads, intake, exhaust. all are factors.

first post says 305 so that was the assumption

 

Some performance cars did come with Holleys, a very few came with double pumpers. The factory tends to do what is least likely to cause trouble with ignorant customers.

No, q-jets are air valve secondary. There is a difference.

 

I also have a ahrd time believing the engine had a tendency to "almost catch fire" or whatever due to any reason beyond bad(read: old) gaskets in the carb or bad seals on the fuel lines.

Ive seen Holley DP's do amazing things in race cars with autotragic transmissions and I've seen them get excellent gas mileage on the highway and calm street driving. It's all in the tune. If you dont want to tune it then keep the engine factory and keep the factory carb on it. The QJet is a good carb, also, for a LOT of applications. Choosing a carb is just about which one you're comfortable tweaking and how good you are at estimating airflow requirements for your build. In a lot of cases the QJet is more than capable, but if you dont want to learn to tune it then that's fine.

The 1969 Z28 (DZ302 engine) came with a Holley double pumper on it.... just sayin'.

 

Not to argue merits of the holley versus Q jet but that holley does have its drawbacks. First you just said it needs to be rebuilt. That is probably partly why it tries to catch fire also. We do not know the size carb but the jet sizes need to be looked at and maybe replaced. If the carb was trying to catch fire it sounds like it was backfiring up through the carb. Anyone familiar with Holley carbs knows that the older carbs are prone to power valves being blown from a backfire up through the carb. It only takes one time. A blowout preventer can be installed to stop this but requires proper drilling etc. I ruined a plate trying it. If the power valve is blown out it will leak fuel into the carb.
Will it bolt up depends on whether you need a square bore carb or a spreadbore carb for your intake. If you have a square bore carb you can buy a thin adapter plate to spreadbore intake. A spreadbore carb to a square bore intake will require a taller adapter plate thus affecting the under hood clearance.
Then you need to think about the necessary throttle and trans cable adapters that might be needed.
Can you use it? Maybe. Is it the best choice? Depends on how well you can get the carb tuned to the motor. It could be trial and error.
I am running a double pumper on my boat and love it. It is normally running just above idle or wide open though.

 

You know that im just trying to help And I wasnt trying to prove anybody wrong or say that the double pumper carb is bad. I am just going by my own experience with them and other carbs i have tried over the years. Im not saying Im right or wrong but look at the sticky of how to choose the proper carb and fuel pump by jester. And you will see that everybody has their own opinion. Once again Im sorry if I ruffeld anyones feathers

 

I don't know anything about the motor till the car is home and I can tinker with it, I can however try to look up the carb since it is sitting in the shed.

 

Update: My dad told me not to use the Holley in my car because it needs a $300 carb kit....

 

Late to this thread - Fwiw as it happens I have just recently done a direct comparison between similar vac sec and double pumper carbs, on my 350/700r4.

Just replaced my 4175 speadbore vac sec 650 Holley with a 4165 sb dp 650 Holley. The former was falling apart, and I had the latter sitting around for years unused.

Cleaned, re-kitted, and re-tuned the dp. Found no difference in manners, and the same performance and mpg (although not great mpg!) if I largely keep out of the secondaries.

Much better performance when I get on it. Worse mpg if I get on it often, tho not by a whole lot.

That can't be right - my speadbore Holley's are considered oddball, but the rebuild kits were only about $75 each, and that's here in Oz where we pay double for anything like this.

 

you are right, they are not that much. $42

http://www.jegs.com/i/Holley/510/37-485/10002/-1

its best to leave it as it is. dont change anything on it. you are young, im 20 and take my advice. its better to leave it go. i have not had a dependable car since i was your age. why, because i cant leave them alone and parts break. its no fun driving mommy and daddys stuff around. im currently sharing a car with the wife and its a pain.

if you want to go fast, build a motor on the side, just because you know nothing about the motor. and take a day to swap them. MINIMIZE your downtime.

 

I don't think I will tinker too much under the hood, I need a car that I can drive around when I turn 17, I still have to drive with the rents.... what a pain. gotta love learning stages, sad part is I drive allot better than the other "L" stage drivers out there, I can parallel park and everything yet I have to wait to November to move out of the "L" stage.

 

i can understand that, i was driving a 95 dodge caravan at 16, how embarrassing lol. but it was the most dependable car ive ever had, drove it for 2 years and never left me stranded and got great mileage.

you can be the best driver in the world, its everyone else you have to watch out for. you will see it the more you drive, people are f$@^ing nuts. especially teenage girls, yet our insurance is higher. good luck to you and your car. enjoy it

 

Yeah my first car was a 88 Camaro, Im in love with the F - Bodies haha, Dodge Caravan man thats hurting, atleast it was good to you, im sure you had some good parties in that though

 

yeah, me and my friends called it the bang bus find out what gears you have in the rear, best bang for your buck would be a posi unit and a set of gears

 

I have a posi in my T/A its a 350 auto. I think its stock gear ratio. 700R4 tranny and no A/C **** A/C.

 

if your not going to be on the highway much 4.10s would be perfect, if you are then 3.73s would be perfect.