RedRokkit

Ok Guys Ive been looking for a new(ish) carb for my Stock 84 L69 5spd Trans Am. Ive read that a Mechanical secondary (dual feed) unit is the way to go on a manual trans - correct? what cfm? What brand? What MPG should I expect? Anyone know where I can pick one up for cheap? Ive looked and found some on Ebay but they all are either WAY overpriced for what they are or extremely OLD. If I do buy an affordable one it will most likely need a rebuild -How difficult? Is this a task that can be handled without any specialty tools? I really dont want to buy any whatchamajiggs that will only be used once. Anyone have any to sell that are reasonably priced? Ive read on here that you can find a good used Holley starting around $50 to $75 -but I cant find any for less that $200 -and thats for one needing a rebuild, then I have to buy a kit for $30, then rebuild it..... WTF? If I spend that much I want it to run out of the box. And again I dont mind doing a rebuild, as long as its not too difficult and I wont have to invest a whole lot into specialty tools.
I was looking for a 650 holley 4150? with Mechanical secondaries (right size?) but every one Ive found is either close to $500 or some huge 750-800 cfm. HELP! TIA for the help.

84 z28

Before you go any futher is your car still computer controled ?

RedRokkit

Yes But I do know that Ill have to replace the Distributor .....Is that all Ill have to swap along with the carb?....This is one of the reasons that I want to swap it out, Id like to get rid of the CCC...Its not working worth a damn, Hell I might be in "limp mode" for all I know......I get like 12mpg and I can barely afford to keep gas in it. The A.I.R. pump has been removed and I have 10 or so vaccuum line that have been disconnected along with a few electrical wires that have been cut. It runs PIG rich, Like acrid, eye stingin, white cloud of exhaust when I hit the gas. I Im lost as to where to begin to get it functioning correctly.....Unless Five7Kid wants to hold my hand and give me a step by step on how to rebuild my CCC Q-Jet and give some Ideas as to where all the unhooked vaccuum lines and electrical go.....I mean my O2 sesors arent even hooked up (lines have been cut) Cost is a BIG factor in this for me......If I can get the existing system working for less than the cost of a new carb Ill fix it.....But Rebuilding my Q-Jet, buying a new A.I.R. pump, vaccuum lines, Map sensor, 2 new O2s, and all the divertor valves or what ever you all them, EGR, and whatever else Im missing to make the existing system work has got to be more $ (and headache) that just replacing the dist and carb and gutting all of the engine controlled electronics.

84 z28

Just replacing the carb and distributor is going to screw with the ecm. Either go all the way and rip all computer controlled stuff out and replace distributor,carb and tcc lockup. Or keep(rebulid)/replace the quadrajet with another one. I believe the quadrajet is rated at 750 also. No knock agaisnt you but your only talking about a HO 305 with 190 hp. Keep it stock and just get a new free flowing exhaust.

84 z28

Tare the ecm out and unhook the wiring harness and all connections. Get new dizzy and get a new carb heres a couple

http://shop.ebay.com/i.html?_nkw=650...4160&_osacat=0

RedRokkit

Not Tcc lock up here- Got a T5. And this is less about performance and more about getting rid of the Acrid exhaust that follows my car....It is REALLY smelly And Id like to get better MPG. But I wnt a good enough unit so I dont have to buy another Carb when I either Rebuild and S/C this 305 (just for torque on the street) or swap for a 350 ( I can get a used Shortblock from the local Pick and pull for $80 or so)

RedRokkit

Ok First Question, My Q-Jet is a spread bore, right? So can I replace it with a Square bore or do I need an adaptor? Second, Are all Double pumpers or dual feeds Mecanical secondary units? I read that if you have a manual trans that you dont want vaccuum secondaries. Third what CFM, since my ccc Q-jet is a (capable of ) 750 CFM is that what Im shooting for? I talked to some guys that said that even If I plan on Upping to a Mild 350 that Id only want a 650? Lastly Ive seen a lot of carbs on Ebay that have the choke removed Id assume that this is bad for Winters in VA....Can I just reinstall a choke on the carb if I buy one without? Conflict or confirm? Thanks for the help.

84 z28

You need an adapter or a new intake for the new carb.Not all double pumpers(4150) are mech secondaries some are vac.And if you have a maunal trans the optimal performance carb would be a double pumper. If this a daily driver and not beat on a vac secondary might work better.And for a mild 305 or 350 for the street a 650 is about all you will need.

RedRokkit

Ok thanks. It is my (fixer upper) Daily Driver.... just a couple more questions.....What else do I have to replace if I swap out to a Holley carb, Just the Distributor? Is that all? and What all can I take off my motor now that the CCC is gone? Can I remove the whole ECM? Charcoal canister? Map Sensor? EGR? Anything Else? Im getting some Block huggers to replace my manifolds and get rid of the A.I.R tubes and O2s, and Im getting a brand new cat-con to help with emissions.

Z2887

If I can find it, I have that adapter. Spreadbore to squarebore. I think I know where it is. If you do this let me know and its yours. PM me your addy. Also, if this is a driver, go with vacuum secondaries. Tuned right it will run just as good as a double pumper.You will never know the difference. Except by your fuel guage.

84 z28

If you have a t5 just about the only thing you need to replace is the distirbutor unless you have electric fans the you need to hook them up some how or maually toggle them on and off. You can remove the whole ecm and all wiring to it which would all be on the passenger side of the car. All sensors are useless(exception of water temp.oil temp ect) just unplug them with the ecm and take the whole harness out. If you take out the charcol canister and plug the lines you will need a vented gas cap. Just a thought but if you buy an adapter for the new carb do a search and make sure the new adapter and carb will fit under your stock hood.

RedRokkit

Thanks for all the wisedom bro, Ill let you know about the spacer as soon as I pick a carb. My fans are already hooked up to a toggle on the dash so at least thats taken care of.....Just for laughs heres some pics of my motor.....I has been BuBBa'd really bad!!! I circled things that have been cut or diconnected and plugged...Its a wonder this thing runs.... SBC FTW!!!!





How hard is it to rebuild/tune a Holley? I do know my way around an engine done swaps, aftermarket turbos & S/C kits, suspension work, Hell I rebuilt the Vette in my avatar from "shoe boxes", but I heard that carbs are finniky and have a ton of gaskets and small parts....and once you rebuild them it can take weeks to get them dialed in...And it would be my first rebuild so Im kinda sketchy about it. any advice is welcomed.

PS - I want the Motor in your Avatar!!!!

84 z28

If thats not a cluster f$%k i dont know what is. The good news is the majority of that stuff will be gone.I suprised your ecm is having a heartattack and throughing codes left and right. Holleys are ok to work on and I believe there is a sticky at the top of the carb forum on tuning them that will help you out. I mostly deal with demons which are pretty much the same carb. If you got free time go into my public profile and check out my cardomain on my build up.

RedRokkit

Oh trust me, as soon as my cars gets warmed up (about two minutes after starting it) The SES light stays on......And GAWD the exhaust smells SOOOO Strong....The ladies at drive thrus HATE ME!!!!! It smells SOOOO bad......Thanks for all the help bro...Im off to Ebay to do some shopping but check back here in a couple I might post some pics of carbs that Im looking at for opinions and info.

84 z28

Just to add something. If your going to stay to a stock level 305-350 you can get away with 600-650 cfm carb. And they dont have to be a 4150.

RedRokkit

Well, Unless I go the " just to be different route" - I will be Swapping a 350 from the JY after I rebuild it (I can get a whole shortblock for $80).... But I REALLY like the idea of a Modded 305.....Get a mild Street/Strip cam and some Vortec heads, rebuild the bottom end, then toss on an Edlebrock Roots Blower,or maybe even turbo it, but I know for a fact it would be cheaper to get a 350, and the parts are cheaper for the 350, and it is more responsive to performance upgrades, ECT......So I will 99% be going with the 350 as soon as the holidys are past..... Tax return
But for right now Id be happy with a car that gets 18-20 MPG and that you cant smell for 5 minutes after I pass by....And a carb that would be at home on my 305 now and later on a mildly modded 350....And as far as me wanting a Holley 4150, that was one of Five7Kids "best picks for our motors" in another thread so I figured I start looking there....But they sure are pricey....so now Im just thinking whatever Holley, or even Edelbrock (Mechanical secondaries preferred) that I can afford....And cost is really gonna be the bottom line for me.....Im broke!!!! Thats why I NEED more MPG....I drive about 75 miles round trip for work, so even a 25% increase in MPG will save me one tank of gas per week!!!!

five7kid

iTrader: (14)

The factory carburetor is the last thing in a long list of what to replace for improved performance. If fuel economy is your goal, you won't replace it with another carb.

Unless your goal is something other than performance, keep your current carb.

Z2887

I had a Holley 750 in my 84. It didnt do too bad. You definately dont want mechanical secondaries though. Like I said before a vacuum secondary carb is just as good for performance. You may be able to get 1/100 of a second faster with a double pumper. I lost no ET when I swapped, but gained probably 5-10 MPG. Everything I ever read, or heard said the same. Except a few people that still think double hump heads are race heads, and think sticking a 3/4 cam in a stock motor gives it 500 HP. WTF ever a 3/4 cam is. lmao

RedRokkit

After looking around on Ebay, I am leaning towards a Holley 4160 - a 650 CFM, Vaccuum secondary unit for less than $100. I can get a rebuild kit (if it needs one) for $30. and a dist from the local JY is $20....So grand total of a carb swap $150 and Ill come close to doubling my current MPG....Now I must ask the Question, Five7Kid - Can I keep the current CCC setup, and get comparable MPG for less than $150? If so Ill probobly go with it - But Ill need alot of help from you.....thats why I wanted to guage the pros and cons of switching to a Mechanical secondary unit.

84 z28

First you need to figure out whats all disconnected and not working and hob cobbed on your car first. Its gonna run like crap until all that is fixed.Then you need to figure the cost of those repairs versus the cost of option "b". Atleast thats what you sound like your saying whatever is more cost effective for you.

RedRokkit

You got it - That pic I showed is right after I got the car - since then I have gone thru and blocked /or reconnected most of the vac. lines, some made the car stumble when blocked/connected, so i just left them alone. I have mostly figured out what has been BuBBa'D and it includes the EGR system, the O2 sensors, all of the A.I.R. tubes on the manifolds, the Map sensor, and pretty much every thing else that has to do with emissions. I seriously doubt I can buy and reconnect all of that for less than $150, but if I can Ill go with that. And the reason I was leaning toward a mech secondary unit is so that when I upgrade to a 350 this spring, I wont need to buy a new carb, because in another post Five7kid said the Holley 4150 was the best carb for a 5spd car, but now I know that Ill get better MPG, and Vac secondary units are cheaper.... but in the meantime Ill get better MPG in the 305.....Make sense?

five7kid

iTrader: (14)

What are you trying to "fix"?

Sorry, I haven't been able to figure that out with in this thread.

RedRokkit

I Have a carb that is running extremely rich ATM, gets HORRIBLE MPG and pukes an acrid cloud as soon as I let off the throttle, Oh boy does it stink.......I was trying to guage whether or not it was a good move to step up to a after market carb to improve the gas mileage and drivability, which right now SUCKS.....I mean I dont have alot of $$ to spend on my car ATM, but it would help me save if I only had to put 3 tanks per week instead of filling it up almost daily. Im pretty much after a quick, easy, cheap fix - toss on a new carb and dist, and Bam - 20 MPG as opposed to 12, and I dont look like Joe Dirt crusing down the road.....And since I plan on upgrading to a 350 in the spring I would like to carb I buy to function well enough on the 305 Ive got, and still be enough for the 350 when I get it later so I dont have to buy a new carb later because they are not cheap.....but if I can get the system I have on now (CCC Q-Jet) to fuction worth a damn for less $$, Id go for it, so I could put off buying a carb until spring -Tax Time!!!! But I think Id be better off just buying a new carb now then trying to fix the clusterfukk of a carb that BuBBa left me with - I have no Idea how its still running with the amount of disarray thats under my hood - but if you Know how I can get it functioning properly Im all ears.......

Z2887

IMO, you were on the right track with the 4160. It will be plenty for your 350 too. Thats what I've used on almost all of my cars. I put the quick change spring,and jet kits on them. That will make it easier for you when you switch over to the 350 too. Because when they need to open, and your jet sizes will change when you swap engines.

five7kid

iTrader: (14)

I completely disagree.

First, if you want a carb that gets the best possible mileage, you've got the right one now. Something is wrong, but it probably is NOT the carburetor. If it is the carb in some way or another, a simple rebuild and possibly an internal component or two not included in a rebuild kit will get it running properly.

Is your SES light coming on? Does your SES light work? If it is coming on, have you pulled the trouble codes?

Second, a vacuum secondary Holley is the wrong carb in every way. First, expecting it to get better fuel economy than a CC q-jet. Second, because you have a T5 - NEVER put a vacuum secondary Holley on a T5 car!

Third, since the only carb other than the CC q-jet you should ever consider for a T5 car is a mechanical secondary Holley, what you need for a 305 is not what you'd need for a 350. If you pick the right carb for the 350, it will be the wrong one for the 305 and vice versa. The proper carb for the 350 might "run" on the 305, but it won't get as good of mileage as it could if it was properly sized for the 305.

Finally, from your pictures, you've got a bunch of stuff disconnected from your system. Question: How can you expect your system to function properly when it's been screwed up like that? Some of it went to the A.I.R. system which apparently has been removed (and won't affect carb operation). The vapor canister equipment also appears to be missing. But, can't tell from the photos what all has been hacked up. I don't see the O2 sensor wire, is that hooked up? If not, that right there explains 90% of your problem. Put it back the way it is supposed to be, and go from there.

BTW, that CC q-jet would work just fine on a 350. If it was allowed to work properly, that is.

Z2887

Im not saying your wrong. So please dont take it like that. Why is a vacuum secondary carb wrong for a car with a T-5 ? I've just never heard anything like that before, and dont see what the difference could be. So long as you have the right amount of vacuum to open them, and they are setup correctly. I mean you can make them open pretty much instantly, or whenever you want them to. Fords came factory with them T-5 cars, and got over 20 mpg, and made great power. I personally am a EFI kinda guy. lol So please shed some light. I definately agree with all that stuff being unhooked. The 87 Im driving now is a factory carb, that has some of that stuff unhooked, and its mileage is horrible too. I was gonna stick a holley on it, but if you can tell me exactly why a Holley wont work well, I may change my mind.

Z2887

Quote five7kid :
"The proper carb for the 350 might "run" on the 305, but it won't get as good of mileage as it could if it was properly sized for the 305."

I agree with that. The 305 probably only needs a 600.......if that. The only way to get around that would be buy 2 carbs though(without using the current quadrajunk....I mean jet. lol). Im sure he dont want to do that.

five7kid

iTrader: (14)

We'll go through this again (having gone through it in other posts). Start here: http://www.holley.com/data/TechServi...ech%20Info.pdf Vacuum secondary operation is explained at the bottom of the file.

The secondaries aren't opened by vacuum in the manifold, they are opened by the pressure drop created in the carburetor main venturi with air flow. The higher the air flow, the greater the pressure drop, therefore atmospheric pressure on the bottom of the diaphragm being higher than the pressure in the venturi (the top of the diaphragm being connected to the venturi via internal passages) opens the secondaries.

Not exactly. If they open instantly, the engine will bog. That's why they are there to start with, to keep the secondaries from opening too soon.

The Ford and GM T5's weren't created equal. The factory purposefully under-optimizes to reduce customer complaints.

Here's the problem with vacuum secondaries and a manual transmission: Open the throttle enough to open the secondaries, then when you let off the throttle, the closing of the secondaries is delayed until the pressure on top of the diaphragm rises enough. This creates an unloaded-engine-with-open-throttle condition between shifts. That is death to a (3rd gen) T5.

I'm not saying a Holley "won't work well". I'm saying for the OP, the vacuum secondary carb is the wrong type, and in general a Holley is not the right way to get to the goal of improving fuel economy when you already have a CC q-jet. And, a Holley won't fit on a stock intake manifold without an adapter (unless you're talking about the 4165 Holley, which is a spreadbore mechanical secondary carb).

Z2887

Wow. You didnt have to go through what makes them open and all that. lol
I knew that. I just said that to point out you could set them up to open whenever you want.

This is DEFINATELY true.

So its mostly just because a Chevy T-5 is weak ?

Yeah I do agree its not "the best" for his 305. But theres not one thats best for both. So I'd get the one I was going to need

five7kid

iTrader: (14)

No vacuum secondary carb with manual transmission - partially because the T5 is weak, but because of the between-gear RPM flare you'll get.

The best carb for the OP now, with an eye toward a 350 in the future, is the q-jet. It will be the "right size" for either engine.

RedRokkit

Not to sound argumentative, just asking - you said
But the CC Q-Jet is a vaccum secondary? Wont I still get " Between gear RPM flare"?


And you dont think a Holley 650 with Mechanical secondaries work for a 305 now (slightly over carbed I know) and will still work for a mildly modded 350 in the future? That was my original plan. Now Im thinking about keeping keeping my Q-jet but only if I can get it running properly....CHEAPLY-namely less than the cost of a new(ish) carb and new(ish) Distributor. I mentioned in an earlier post on this topic that my O2s are in the manifolds but the wires have been cut, and that niether my map sensor or charcoal can are hooked up either. None of the A.I.R. tubes on my manifolds are connected. My EGR isnt either. None of the Diverter Valves or whatever they are called, along with many vaccuum lines that are on my underhood Vac Routing Diagram are present. And Yes, my SES light comes on as soon as the car warms up. And that is just what Ive noticed wrong with the car, Ive no doubt got other problems with the system as well. My goals as of right now are to improve my MPG to around 20 or so, and the lose the putrid Joe Dirt cloud....you know the acrid RICH exhaust..... inexpesivly as possible right now, and I still think that that replacing the carb and dist is the cheapest route at about $150 - $20 for a used HEI mechanical/vac advance dist and $130 for an Ebay Holley 650 w/ mechanical seondaries and rebuild kit.......But I am looking around to see if I can get the parts to help make the Q-jet run properly...and I did find a working A.I.R pump for $5, but the shipping was $30, and I havent even gotten into the O2s and EGR system.....And things like those I have to buy new ( I wouldnt trust the JY for parts like that) But no matter which route I take be assured it will be the cheapest way to improve my mileage from 12 to ~20MPG....Its results and cost that are important to me, not which name is on the carb.... for me the better system is the least expensive one that I can get working properly.

RedRokkit

And just to ask it as directly as possible:What systems control, or affect the carbs proper operation? How can I get my get my Q-jet to function properly? What exactly is needed for the carb to run a stoich A/F ratio? You said the A.I.R. pump has nothing to do with the carb, so is it as easy as hooking up the O2s and the vapor canister? Should I keep all the vaccum lines that go "nowhere" on my carb plugged? What else should I replace / reconnect? What about the Map and EGR, do they affect the A/F ratio?

Z2887

What exactly do you mean by "flare" ? The way it sounds to me is, your saying basically your RPMs dont drop instantly when you let off during shifting.

IMO, a Q-Jet is never the right carb for anything. lol

84 z28

The rpm's dont drop if you know how to shift.

Z2887

Thats what I was thinking. You dont want them to drop, and if your not racing your secondaries arent open anyway. It just doesnt make any sense to me. I mean I think I know what he's saying, but I dont see how it makes a diference. Especially when millions of cars have been put out by the factory with a manual trans, and a Holley vacuum secondary carb. Also like he asked. Why wouldnt the Q-Jet do the same thing ? Since its a vac. carb too. I've owned a bunch and couldnt ever tell the difference in anything when I shift comparing the exact same car with EFI on it. I shifted at the same RPM. They(RPM's) fell off seemingly at the same rate.

84 z28

Your worrying about it to much. Opinions are like @$$holes and everyone has one. I have seen people use alot of things for alot of different applications and just cause someone says something dosent mean it cant work. Can a vacuum sec carb work on a manual the answer is yes. What is the best for a maunal and best for performance is a double pumper.

five7kid

iTrader: (14)

No. The air valve of the q-jet will delay opening, but closing would be a function of the throttle butterflies, which are directly connected to the accelerator pedal.

There is no way to close the secondaries of a vacuum secondary carb with the throttle itself. Doesn't matter how far in the air your nose is.

RedRokkit

I am extremely confused by this statement.....That is why I shift, to get the RPMs to drop....5000 rpm in 3rd, so I shift to 4th, and Im back to 2000rpm......Did you mean "The RPMs dont FLARE if you know how to shift"?.....I hope I dont sound like a DiKK, I just went thru and read every post on this topic and I was head scrathing after I read that.....

chrispy383

Mech. is the way to go for a standard trans. It will eliminate hessitation after shifts, but will eat more gas.

RedRokkit

Only If you are flooring it....From what Ive read, if you maintain "sedate" or normal driving habits, ie: not shifting aggressivly, the difference should be negligable......

Grumbles

Whelp I have a 4165 in pieces and a 600 cfm vac secondary on the way to work with in the meantime...I'll let you know if my tranny grenades so you can avoid making the same err of judgement :P

EDIT: Don't think Five7 is talking down to you either, he only linked you to the sites so you could better understand WHY he's saying what he is, and provide some helpful documentation that might shed a little more light on it that just a couple sentences on an internet forum could.

Let me ask YOu something Five7. How much should I expect to pay out to rebuild a holley 4165? I gutted one, and it's a nightmare in there. I don't really know what to use to get the gasket off or where to get all the components that rusted out, so i want to take what i have to somebody and have them fix it, heh.

RedRokkit

I know that Five 7 means all the best with his advice....and I hope he continues to post in this or any other thread.....Thats why I post here, to gain knowledge...and he seemes to have LOADS.

I found a rebuild guide for a different model Holley that I was eyein online...Ill see if I can dig one up for the 4165....but like you said, rusted parts....UMMMM, I might leave that up to a shop to rebuild as well....If I may ask for pics, Im just curious and thirsty.......

RedRokkit

Been doing some browsing around the net and Seems that no one has anything good to say about the Holley 4165 - especially when compared to any Q-Jet ......Just thought Id share. So if I go Holley, Ill definitely be going with the 4150.

84 z28

You are right about that and the only statement I said was about dropping rpm and if you new how to shift it woudlnt happen. But what I have been posting all along is that you can make a vac secondary workable if its just for daily driving and your not out to race or beat on the car. Otherwise like I have been saying for a manual car the way to go is a double pumper.

84 z28

What I meant was if you know how to shift your rpm's wont drop as in speed shifting. When your racing a manual you keep your foot on the gas at all times press the clutch in as fast as you can and shift at the same time. At most you should on lose a couple hundred rpm not a 1000 rpm or so.

RedRokkit

Ok Cool....I just wanted to be on the same page........I really dont know $hit about speed shifting, I always lift the gas, even if Im racing, I have speed shifted on a Bike and the way it tached up in that milisecond it took to shift....Yikes!! I couldnt imagine doing that to my car esp with the amount of time it takes to row thru the gears, my motor would probobly blow before I made the 1st to 2nd shift, LOL!!!.........So am I correct in believing what youre saying that I shouldnt worry much about Mec VS Vac Secondaries as long as dont abuse the hell out of it like you said before.....(see I got it the first time) and that vac secondaries are usually better on gas........I still dont see why the "RPM Flare" seemingly doesnt apply to vac secondary Q-Jets though.......AGAIN, NOT TRYING TO SOUND LIKE AN A$$ JUST TRYING TO GATHER INFO TO MAKE THE BEST EDUCATED DECISION.....Because if the Q-jets are suceptable to RPM Flare it will be a factor in the decision I make.....and if any one is wondering, Im still undecided, but Ill let them know which direction Im leaning torwards(today:P) Anyone feel free to chime in.

five7kid

iTrader: (14)

Which is exactly what you should not do with a T5.

84 z28

I know that and so does the OP. This carb is going on his daily driver in which he has said the it will not be beaten on or raced its just for commuting. In that instance I can say the vac secondary would be ok to use. Do you actually read these posts or just throw out your opinoins randomly ?

five7kid

iTrader: (14)

Why waste my time doing that?

Random is good enough. Every once in awhile one sticks.

84 z28

lol