[61Airstream]

Recently swapped in a crate 350/290 hp motor into my '87 Camino. Can I put a non computer controlled carburetor on it and leave the distributor and EMC intack? My machanic says it would run great and only have the "service engine light" on. (I'd just remove the bulb). Emissions testing is not done in my state although I plan to keep the air pump and run air back to the cats.

Jim

 

[darbysan]

Without the feedback from the carb, the ECM will go into Limp Home mode. The distributor will not advance properly ( since it is controlled by the ECM), and will run poorly. If you remove the CCC carb, you must also remove the Distributor and ECM, and provide a means to lock-up your trans converter.

A well tuned CCC carb is as close to Fuel Injection as you can get, and will give the best performance and mileage possible from a carb. Think of it this way- the ECM is constantly tuning the carb for 14.7/1 Air Fuel Ratio. A non ECM controlled carb is just guessing at what the A/F ratio is, based on what jets were installed in the carb.

 

[steelybill]

Others here are more familiar with the ECM controlled distributor, but I believe you need a stand-alone HEI distributor, with vacuum advance & centrifugal advance. Without the carb with the throttle position sensor, and temp sensors etc, that distributor likely wont advance the timing.
So, bottom line...you need to change both. Hei distributors are fairly inexpensive now anyway. A new carb wil be more expensive than a new HEI.

 

[61Airstream]

Thank you both, that's what I was thinking. I don't know why my mechanic would even suggest it. He runs a racing and performance shop. Maybe he just hates computer controlled emission equipment.

Jim

 

[87next2last1]

Get your Comp control carb rebuilt & will run like new !!

 

[61Airstream]

I've been reading and trying to understand Doug Roe's book "Rochester Carbuetors". On page 100, he says "Adding valve overlap and lift with a racing cam allows the engine to breathe better at high rpm. But worsens manifold vacuum at idle and low speeds-creating distribution and vaporization problems.
The engine becomes hard to start, idles roughly or not at all ...and has very poor pulling power at low rpm. The conditions are especially noticeable when a racing cam is matched with a lean, emission-type carburetor. "

I wonder if this is what is happening to my crate 350/290 hp? It pulls alright at low speed, but idles rough and sometimes stalls.

Jim

 

[61Airstream]

I sent my last post before I read 87next2last1's post about getting my existing carb rebuilt.
i would like to get a rebuilt carb. Should I have any changes made to it. There is a guy on Ebay that says he can modify the CC Quadrajet and I've sent him a question about what type of changes he makes to them. Earlier, he wanted info on the cam, intake manifold and headers, but didn't go into what changes he could make. I assume the metering rods in the secondaries, but don't know what else.
I don't think Mountainman works on the CC Quadrajets.

Jim

 

[87next2last1]

You can call or send Mountain Man A email & tell him what you have & what you want !
Mountain Man Fuel Systems
479-639-2022 or [email protected]

 

[EdontheBeach]

amen! call mountain man - there are plenty of people here who will attest to the quality

 

[61Airstream]

I've already spoken to them.

Jim

 

[Wayne Parrish]

Jim, I recently went thru the same scenario. I replaced my carb with a Mountain Man non-comp. carb and took the computer out ,period ! You will need to put a vac advance dist. in it and I am using a MSD with MSD wires and absolutely loving it. It runs so good and so positively reliable ! Ecah time you hit the starter it just fires up so fast that its scary. If you need the distributor number I will be happy to forward it to you. There is NO BETTER than Mountain Man to buy a rebuilt carb from. When you pull the carb out of the box you will swear its a BRAND SPANKING NEW CARB !! Ted and Ardell are the best ,PERIOD !! Any way I can help let me know. Wayne

 

[61Airstream]

Thank you. I may go that route.

Jim

 

[Wayne Parrish]

Jim, I'm running a 2004-R overdrive tranny w/a 2.73 gear and with the setup I described I get 18 areound town and 25-28 on the road,so its a good setup. If you order a carb from Mtn Man tell them what type driving you are doing and whether you want economy or power and he'll set it up for that. If I remember correctly it cost me about 6-700 dollars for everything. WP

 

[61Airstream]

Any problems with emissions testing?

Jim

 

[JJLT1]

My machanic says it would run great and only have the "service engine light" on.
He runs a racing and performance shop. Maybe he just hates computer controlled emission equipment.

i think we just found the problem..:dontknow:
if he cant hook up to the computer and see whats going on??
he's probly not going to fix it, without just replacing random parts.. if its a sensor??

this is straining my memory,, but i thought you found that problem (rough idle) with more initial timing??
from the other posts it sounded like the chip would help,,sorry that wouldnt work..
the rough idle is probly messing with the map sensor (vacuum) the computer is getting bad info..

does adding timing smooth out the idle??
if so the chip with a better timing curve should help,,more initial timing with the same total advance..

the racing cam in the book is not what u have,, the cam in the 350 probly does have a little
more overlap,, i dont think its a computer cam but its not a racing cam,,
and a little more initial timing will usually make it act better..:dontknow: what yall think..:texas:

 

[Wayne Parrish]

Jim you said in your initial post that emissions were not required in your state ? No problem with emissions here in NC either.

 

[darbysan]

If mountain Man carbs doesn't do CCC, they can be obtained from Cliffs Performance http://www.cliffshighperformance.com/index.html , or Sean
Murphy http://www.smicarburetor.com/products/sfID1/28/sfID2/9/sfID3/34.

The cam in the 290 is not much different from the L69 cam. Should be absolutely no issue for a Qjet. Before you spend money on the carb, be sure there are no vac leaks. If the carb ran fine on the 305, it should be fine for the 350.

 

[gilby]

Thank you both, that's what I was thinking. I don't know why my mechanic would even suggest it. He runs a racing and performance shop. Maybe he just hates computer controlled emission equipment.

Jim

...I can't blame him,I hate the darn things too, that's all you need, a BIG solar flare hits this planet,all of the electronic will be knocked out,that means all of those computer controlled cars aren't going to run..Back to horse and buggys....oke::beer:

 

[Wayne Parrish]

Mountain Man does all the Quad carbs but why would you want a computer to control anything when you can do w/out it ?

 

[61Airstream]

The only problem with the 305 was that I was getting code 53 EGR after a few minutes of highway driving. After pulling the intake off it was complete clogged up. We cleaned up the intake, put a new EGR valve and solnoid on and it still gets the same code on the 350 as it did before. Could this be the carburetor?
Know anyone that has the L69 Prom? If I don't find find one, I'm going ahead and have the guy in Calif. burn a custom prom. Everyone, (except my mechanic) is telling me to get a new prom.

Jim