Mikeroc283

I need some suggestions for a replacement carb for my car. Since i have the 700R4 i need a lockup converter switch or something i was told. Any carbs i can switch to without the switch if i even need it would be great to know about. I really need to change the pos factory carb out asap. I want a 600cfm or 650cfm. I just dont know what i can switch to.

midias

You don't mention any modifications to your car but stock and minor bolt ons the factory carb will give you the best performance and MPG

84ws6ta

If you're ditiching the emmissons equipment, then I would suggest going with a non computer controlled Rochester. Contrary to what a lot of people say, it's still a good carb. Switching to any carb other than the one that came with the car will require a new distributor along with buying a lock-up kit for the transmission.

1982Z28Modified

It has been my experience to put on a Holley 4175. This is a direct bolt on replacement for the Q-junk. You can leave the wires dangle that went to the carb with no ill effect other than SES light.


If you decide to junk the emissions crap that would be a step in the right direction.


The 4175 comes in two different setups: the 0-80555C and the 0-9895. Both are 650CFM. Both are 50 state emissions legal. The only difference is the 9895 has a vent for the fuel bowl to the charcoal canister. Both have electric chokes and vacuum secondaries.


Drivability. You will notice an immediate improvement. Like, OMG why didn't I do this years ago!


Furthermore, Holley has been perfecting there carbs continually. The Q-junk was last produced 30 years ago! What you get with a q-junk is 30 year old tech that was not that good in the first place.


Some pre-eminent prima-donnas will claim the leaky q-junks are just fine. Bolt on a Holley and find out.

naf

iTrader: (7)

Without also swapping out the computer controlled distributor I'd expect less than spectacular results.

You should also wire in an alternate method for converter lock. Trans heat is bad.

84ws6ta

"Some pre-eminent prima-donnas will claim the leaky q-junks are just fine. Bolt on a Holley and find out."

A properly rebuilt Rochester does work just fine if not better. It's usually the people that can't tune a Rochester that claim they're junk.

There are also some of us who would like to keep their functioning factory cold air set-ups. Can"t do that with a Holley.

Scorpner

iTrader: (4)

I've swapped to Holley and also ran repaired emission Q-Jets. Having first hand experience with both, I agree Q-Jet works great if you have them repaired properly. Get the throttle shaft bore checked and repaired if needed.

Signed,
pre-eminent prima-donna

1982Z28Modified

What you pre-eminent prima-donnas choose to ignore is that the q-junk is 30+ years old tech that was mass produced by the millions by essentially trained monkeys. Did you know what they do with rejects? When they needed more production, they would go through the reject pile and fix what they could, or just ship what they needed and let the dealer handle the complaints. The Big Three does everything based on cost. Not quality, economy, or safety. Cost, cost, cost.

Scorpner

iTrader: (4)

Wow! the other replies must have went way over your head.
Including the satire of name calling.

Do you have any actual facts other than useless comments of replacing something new is better than something that's been in service for 30 years?
From what you have previously posted (in here and other threads) you appear to have very limited knowledge of production processes, and some of the above is common across most industries.
Rejects are typically sent back/reimbursed to the supplier under a predetermined contract. Usually for free or even at a penalty if it holds up production. Rejects are also incorporated into a database, analyzed, and used to make improvements in the next suppliers production run.
Yep, if you work only on the production floor all you're going to see is concern over production costs, that's only a small part of the system.

84ws6ta

I work for a supplier to the Big Three, Toyota and Nissan. I can tell you that any part that fails, is immediately sent back. In certain cases, an entire shippment can be returned if enough parts are suspect. Anything sent back is reimbursed. There is no throwing parts in a pile for possible future use.

That being said, as for Holley carbs, the design hasn't changed in the decades it's been produced. Sure minor improvements have been made, but overall the design is also 30+ years old and is also considered 30+ year old tech with the advent of computer controlled fuel injection. It's also the reason that Demon carbs came about. The guy that started Demon carbs worked for Holley and decided to build his own because the lack of design improvements and production process improvements.

nhgator

My q-jet doesn't leak,had a local grey beard carb pro re-build it and works fine,didn't have to hack up my mostly original car and change the distributer and all the crap that goes with it like tc lock up etc.

1982Z28Modified

Never argue with idiots. Then drag you down to there level and beat you with experience. You two factory rats know everything.

Scorpner

iTrader: (4)

That's good advice. Refraining from name calling, and simply stating your opinion as an opinion (not fact), would go a long way towards attaining your goal of not arguing with others.

I for one would like to be able to post my opinions here without being called a pre-eminent prima-donna, idiot, factory rat or anything else you can think of.

1982Z28Modified

Well Scorp, if the boot fits... COST COST COST. That's all GM, Ford, and Chrysler care about. I knew people who worked at GM factories. I know Ford guys who worked in the Carb labs until carbs were phased out.


Why do you think the plugs in the Q-junks leak? GM could have spent the $$$ to fix it. Instead, they epoxied the units that failed and shipped them to the engine plants. That was the cheapest fix they could get away with.


I thought this site was about the free exchange of ideas... but it usually comes down to people jumping all over you because you dare suggest putting on a different carb (Holley).


So Scorp, 84, and Gator. Enjoy your stock. Myself, Holley carb, ZZ4 intake, headers, 3" exhaust, no emissions except PCV and canister. Serpentine upgrade. Runs like a raped ape with original LG4.

84ws6ta

"I thought this site was about the free exchange of ideas... but it usually comes down to people jumping all over you because you dare suggest putting on a different carb (Holley)."

Wow dude, you call people that favor Rochesters "pre-eminent prima-donnas", "idiots" and "factory rats", yet claim that people are jumping all over you because you suggested going Holley? Get a grip on reality. The original post was about suggestions for a replacement carb. I gave mine and you immediately jumped on me and anyone else that didn't agree with you. Now you're going to cry foul?

Scorpner

iTrader: (4)

Yes, I agree with you on the cost issues. IMO, they could have done a lot to the Q-Jet to make them better, but also in my opinion Holleys have their faults as well.

FWIW, I purchased a 4150 brand new and after some time it developed similar leaking problems. What I've learned from that is that they are more sensitive to fuel pressure requiring an additional regulator, plus the needle valves and power valves also can contribute to this. In that respect, and from my viewpoint, both carbs have issues with the same thing even though mine was newer. Not trying to argue, just saying I've had issues with both.

Yes, this is supposed to be a free exchange of ideas and that would be great. That said, the most you can do without starting an argument is make your case and stick to the facts, like the facts you just mentioned about the leaky plugs on the Q-Jets. That's good info, and people can't argue about facts, but they can about opinions and to be honest some of the comments were inflammatory.

FWIW, the throttle shaft bores on the Q-Jets wear out as well. However, there are fixes for both that and the plugs.

1982Z28Modified

Well Mr 84, that's the way its been. I say get a Holley, and the PEPD's right away rag on rebuilding the q-junk, rag on removing emissions, and so on. BTW, I didn't insinuate that you or anyone else was an idiot. I said don't argue with one.


To the Scorp, I myself went the q-jet route. Went through it with proper gaskets, accel pump and so on. Ran but not right. Well, after spending about 300 in having an "expert" rebuild the CCC, it never ran again. That's when I junked the q-junk, got a 4175, MSD mech/vac dist, removed computer, emissions, exhaust, and now I have a daily driver that always turns heads.


Personally, I have no experience with the 4150. I prefer direct bolt on replacements.


As far as performance and mileage are concerned, my 4175 is far superior to the q-junk I had.

naf

iTrader: (7)

so everyone is getting along now? I'm sure you all scared off the original poster though, probably traded in for a Fiat.

Scorpner

iTrader: (4)

The place that rebuilt my Q-Jet did them for the local dealerships so they did know what they were doing. It was pretty much a bolt-on and run after the rebuild. It was for my DD, worked perfectly summer/winter, passed emissions etc. until I sold the vehicle. Sorry to hear about your experience but it sounds like they didn't know what they were doing.

FWIW, the 4150 is Holley's bread and butter, pretty much the standard of what they produce.

Scorpner

iTrader: (4)

Sadly it's probably not the first time concerning this subject. It's almost as bad a bringing up abortion or politics.

sonjaab

AMEN!

five7kid

iTrader: (14)

Hey, I know, why don't we talk about the "best" engine oil to use...

Okay, original poster: You said, "I just dont know what i can switch to." There are two answers to that question: 1) Nothing but the original type q-jet; and 2) Most anything you want.

Regarding #1, there isn't any direct replacement for the factory CC q-jet, even the Holley 4175. Yes, the 4175 may bolt on to the original intake manifold, but you can't even use all of the original bolts. It doesn't have an electric choke, and it doesn't interface with the computer. There really isn't much advantage to using it (and, yes, I have used it). A properly built and adjusted CC q-jet(meaning to factory specs in both cases) really does work well on a stock, street-driven 305.

Now, #2: You can put pretty much any type of carb on you want. You'll just have to replace other things. If you put a square-bore carb on (Edelbrock, Holley, Demon, Quick Fuel, etc.), it won't bolt on to the factory intake manifold without an adapter. Personally, I wouldn't do that, I'd replace the intake manifold with an aftermarket that accepts a square-bore carb. You'll end up with a slightly better intake, if nothing else, and you avoid having to use an adapter. For the least fuss and adjustment, the Edelbrock (which I don't really like for several reasons) with electric choke is probably the least work to get running.

But, you'll also have to replace the distributor. The factory CC distributor relies on input from the factory CC carburetor, which you'll no longer have. And, since you have an automatic transmission, you'll also need to get a "geometry corrector" for the TV cable. You already mentioned the TCC lock-up switch.

So, replace the factory CC q-jet with an aftermarket non-CC distributor, and buy the carb, intake manifold (unless you go with the Holley 4175, which, remember, doesn't have electric choke), HEI vacuum/mechanical advance distributor, geometry corrector bracket, and TCC lock-up kit. You're probably looking at $500-$700.

Or, rebuild or buy a rebuilt CC q-jet. Probably $75-$400 max. And it will run just as well as any aftermarket choice. And probably get better gas mileage.