I have an 86 Z28 Camaro, factory 305 and factory carb. I'm pretty sure the carb is the quadrojet 4 barrel. I know it has an electric choke.

A mechanic I use for some things from time to time told me flat out that I could not replace this carburetor with a holley or elderbrock, or anything like that.

I haven't done the research into it yet but I was wondering if this is true and if so why? I haven't done much detailed engine work yet, am starting to learn as part of my project car, but I was under the impression that carburetors where fairly easy things to change just going from one carb to another.

Any advice is appreciated. I'm going to be replacing my engine sooner or later and was thinking about going ahead and getting a new carb and throwing it on this engine for now.

 

The best and easiest option is to just rebuild the one you have now. Sure, a carb swap can be done, but after figuring all the adapters and linkage connections and then tuning the new carb to the application.. It just seems like a lot of work for one whom is gunna pull it eventually.

Get yourself a couple of Qjet books one by Doug Roe and the second by Cliff Ruggels..

1. http://www.amazon.com/Rochester-Carb...7875211&sr=8-1

2. http://www.amazon.com/Rebuild-Modify...7875211&sr=8-2

Cliff also sells some of the best q-jet parts as well - http://www.cliffshighperformance.com/carbkits.html

 

I'm assuming you have a LG4 in it now, so your mechanic is right - you can't just replace the carb with a Holley or Edelbrock. You need a CCC (computer command) Q-jet to replace it with. They sell rebuilt ones along with rebuild kits at most of your major auto parts stores.

I actually have a rebuilt CCC carb I'm going to sell on the classifieds when I get around to it. I believe it costs me a little over 200 bucks when I bought it (with a trade-in).

Only other option is to get rid of the computer, but that basically involves switching to a regular non-CCC carb and distributor. There's a bit more to it than that, but you get the idea....The CCC system will work with a 350 too if the carb is your only issue with it.

 

And it's going to depend on your emissions and inspection regulations. Most states require the use of OEM factory equipment, not sure on SC. And I think it's federally mandated, but no one enforces federal law.

In NC, any car older than 1995 doesn't get emissions inspection, just safety (lights, horn, wipers, brakes). And 1995+ cars only get emissions inspectons in certain counties. Those are the counties that everyone pops the hood to look for emissions equipment - even though emissions testing is not required on the older cars, they are supposed to verify that the OEM emissions equip is there. The non-emissions counties no one ever pops the hood. So I go to a non-emissions county to get inspected - that way I have no issues with anyone questioning my Edelbrock.

But - if you have no emissions issues, you can swap to an aftermarket carb. But as mentioned, you'll need a carb, and a vacuum advance distributor. Your ECM will no longer function, and if you have an auto tranny you'll need a method of locking the torque converter as well as a TV cable geometry corrector for your carb linkage.

You'll lose some gas mileage with an aftermarket carb - the stock Quad is the best carb setup to have for mileage and performance, but we do what we gotta do.

 

It's so easy that it is often done when not necessary.

But, as noted above, there are some "details" when dealing with a factory 3rd gen carb. Not mentioned is the mounting to the intake - your factory intake will only accept a spreadbore carb (the q-jet is one of only a few spreadbore choices - most aftermarket carbs are squarebore).

Since you have a 5-speed, a case can be made for going to a double pumper Holley type carb. But, anything other than a double pumper, don't bother - keep the q-jet. It will handle more engine than your 5-speed can.

 

Well thats what I was thinking about a holley 750 cfm double pumper. I know it's a bit to much for my current engine but I figured I would use it when I do the new engine.

But sounds like I would have to do a lot of stuff to get it working correctly? The mounting isn't going to match up? Do they make adapters for that? I'm going to have these same problems when I replace the engine then aren't I?

Right now my ECM to my understanding, controls how much fuel and such is getting pumped into the carb as well as controls when the electric fan turns on and other things. Thats why I had it looked at by this mechanic to begin with, the fan wasn't turning on and it was running really rich. It was because my ECM was reading -40 degrees as the engine temperature at all times, I had to replace my ECM to correct that problem.

What kind of mess am I going to get into when I do the full engine swap? I don't know what else the ECM controls thats going to have to be converted to a manual control.

I should've gotten a 70s model camaro for a project car so I didn't have to deal with all the electric stuff hehe

EDIT:
Oh and as for the smog and inspection stuff. I'm not even sure my smog pump is working on the car right now. I haven't checked into it. There are no inspections in SC anymore.

 

get a holley rebuilt m4med qjet off a canadian third gen a gmpp hei a mr gasket vacuum advance and a timing light new wires and plugs . get the doug roe book and the cliff ruggles book learn how to fine tune it. you'll love the way it performs. aftermarket isnt always better especially with carbs I love holley double pumpers but in most cases a qjet is a better choice. dont get a edelbrock gm stopped using them in the mid 60's for a reason

 

In a manual transmission car, the ECM controls the primary mixture ratio, ignition timing, the EGR valve, and the A.I.R. ("smog pump") diverter valve. It may also run the cruise control if so equipped (not completely sure about that). In later models, it controls the radiator fan (only one of a dual fan set-up, if memory serves), and is also part of the VATS loop (your '86 has a simple switch in the cylinder head for the fan, and no VATS).

A 650 CFM double pumper would be fine for a 350, and not overkill for a 305. You probably wouldn't be very happy with the way a 305 drives with a 750 on it.

If you don't do a double pumper, don't bother with any carb other than your CCC q-jet. There is absolutely no advantage to a non-CCC q-jet.

 

The only reason I was thinking of going with a 750 is because more than likely when I swap the engine it's probably going to end up being a 383 instead of a 350. I figured a 750 would be better for a 383 than a 650.

Maybe I'll just stick with my carb though and see how it does, would I be able to mount this carb onto a 383 block? Would my factory carb be enough for a 383?

 

As long as you use either the same intake (it'll fit on a 383 as long as your heads are the old style), or make sure that you upgrade to one with both square bore and spread bore mounting, then yes you'll be able to use the quadrajet on a 383.

The quadrajet is a 750 carb. But the great thing about them is the spread bore thing. Small primary bores, huge secondary. Just cruising around in traffic and going easy on the gas, it only opens those tiny bores and your throttle response is great, as if you had a little carb on it. But stomp on the gas, the big ones open up and you get the benefit of a bigger carb.