Hello I dont know if this is the right place for this question but here it is. I have an 83 elco that had a 305. I swapped it out with a crate high output 350 from GM. The motor has all the smog stuff on it with the california legal headers. I have the rochester quadrajet on it and I can not get it tuned to run good. I have brought it to the shop a couple times and they said that with the cam that is in the motor they can not get it to run good. In the Original Parts Group catalog there is a company that sells a quadrajet rebuild that is for a mild performance motor. what is so different from the original quadrajet? If the motor needed more fuel than wouldn't the computer adjust for it? I am also open for any other suggestions.

I'm assuming that you have the electronically controlled q-jet. Company I'm guessing that offers up the "warmed-over" carb is JET. Might check with them directly, but I'm guessing a lot of the problem is you still have the 305 chip in it for the comupter. I don't have the ECM manual in front of me, but I know from GM there is a different chip between the 305 and the 350. The good news is JET also sells aftermarket chips, so they may be able to solve both problems. I don't have any personal experience with JET so I can't attest to how their customer service is. You might want to start off with a company such as OPG as you mentioned, or someone like Summit. Good luck.....

Thanks for the name JET. They are actually a different company but they where really nice. I was wondering if anyone has used a JET performance chip in there car? Also I was wondering if anyone has used a high performance quadrajet from JET or SMI or any other companies? I dont want to spend 500 on the Q-jet and probably 150 on the chip if there wont be a advantage of doing so!

Unless you're planning on keeping things relatively stock I wouldn't bother with spending that much money on a new q-jet and chip when you can just get a Holley, Edelbrock, or even the new Summit brand carbs. If you don't want to change the intake right now you can just buy a spread bore to square bore adapter from any Autozone for around $20 - $30 bucks. If you go this route don't forget the throttle cable and trans. kickdown cable brackets. You'll be about $300 or so if you go this route depending on which carb you chose and no computer to worry about. :beer:

Are your issues with the stock carb at all throttle openings or just at full throttle? If it runs OK except at full throttle, you may just need to change the secondary metering rods to give the higher output motor some additional fuel. Q-jet secondary rods are very easy to change without removing the carb and not expensive. Might be worth your time and $$ to pick up a Rochester book by either Cliff Ruggles or Doug Roe. Any replacement carburetor would not be electronic, and would require to de-computerize your truck. Might not work for emission legality either.

Bill

If this helps,, when you change a throttle body / computer controlled small block (post 90's) from a 305 to a 350 you have to get the larger injectors for hte 350, and get the proper prom (for OBDI pre 96).

I think your fighting a MAJOR uphill battle trying to use the stock electronic carburator (assuming that is what the issue is here). Those things were a PITA when everything was RIGHT and matching.

Jason.....the CCC (computer controlled carburetor) can handle a lot of different engine combinations but they do require re-jetting to do it. Find someone who Knows the CCC and can make some experienced adjustments and won't just try to sell you a new carb. On the Monte Carlo SS forums, there are several folks running the CCC on GM crate 383s and turning respectable 1/4 mile times. So, before you sign the Big check, try a dyno tune or whatever with a good CCC technician.
Craig

hey guys thanks. I didnt want to spend the big bucks!! I have already brought it to a shop and they tried but they couldnt get it running good so I am about to give up on it. But I will try and find a place that knows more about the CCC. I want to keep it stock so I dont have to worry about smog here in california. Also wondering if the computer/ chip are the same for 305 to a 350? I always thought that they were the same. Also did GM put a different CCC on a 350 than a 305? I have had a edelbrock on it in the past but I needed to rejet that one as well so I figured that I should just figure out the CCC that way I dont have to worry about smog because I have to get it tested every year!

Jason.....I have run several Performer carbs on trucks and Camaros. To me, they are a "set it and forget it" carb just like the Carter AFB. I have never found them to be mileage carbs, just reliable with some performance potential. I really disliked Quadrajet carbs until I bought this car. Now, I am really impressed with the CCC. I also have the good fortune of a Quadrajet guru in my list of good friends locally. A thought might be to join up with the MontecarloSS.com forum folks. Post up your 5 or 10 postings and then start a thread in the Engine section about your carb situation. You don't have to mention El Camino at all (it really doesn't matter to them at all) but just post your car facts and chat up with them. A lot of them run the CCC and the Monte Carlo folks tend to modify everything. In any event....keep us apprised of your situation!
Craig

thanks craig you have some good advice!!! I will keep you all informed. Tomorrow I am going to call some carb shops and go from there!

The crate engine you have may have a cam (profile) designed for fuel injection and not for a carb. Review the egine spec's with GM.

Good luck.

I have heard that before. I was talking to a shop and he said that the high output motor is designed for fuel injection. But I only heard that from him. would it be possible to make it run good with this cam?
Thanks
jason

How about just installing a Holley Projection fuel injection system and getting the best of both worlds....I've found a couple of them on Ebay and have had good luck with them so far....once you go fuel injection you won't ever want to go back----unless you are like Marv and drag race on a professional level---at WOT a carb (properly tuned) can have a bit of an advantage over fuel injection but the difference is getting much narrower lately and on the street its no contest....carbs are going the way of the dynosaur....................Dan

Jason, which crate engine did you install? Did you change the Knock Sensor to a 350 knock sensor? What problems are you experiencing- give details.
Since you live in CA, you will need to keep all the stock stuff, but unless you have a really radical cam, you should be able to get it to run well with no issues. For a 350, the Quadrajet should be able to handle normal running no issues. You might want slightly bigger secondary rods, but that is easy to fix.

I'm not aware of a "350" chip for the ECM. The only real difference in the chips is the spark advance table. Otherwise, the ECM always tries to maintain 14.7/1 fuel ratio, so it doesn't really care what demand the engine has on the carb, it will open the mixture solenoid to compensate.

The only issues may occur if the engine has a very lopey cam, giving low vacum at idle. This can confuse the ECM (hence the question on which crate engine you chose). If the crate was an FI crate, then it should be no issue. The FI cams were always milder, since the ECM really needs a good vacumn signal for FI.

I was thinking about fuel injection. I was looking at the ram jet from gm performance. If I got fuel injection systems on my car does anyone know if it would be smog legal her in california? What system is the best for the price?

hey darbysan. I have the 350/290 crate. We have to have the timing at around 20 degrees to make it run good. Also my carb is spilling over on the secondaries causing the rpm to fluctuate constantly and not run smooth. I have no power pretty much all the time. I did not change the knock sensor didnt know that there was a difference!

The 290 HP engine is not a FI engine, and does not have a radical cam. You should be fine with that engine.
I'm assuming you are still running all of the computer stuff, and it is all hooked up. First, the timing should not be that high. Did you unplug the 4-pin connector from the distributor before setting the timing? Also, did you re-use the dampener from the 305, or did the 350 come with a new dampener? Sometimes, the 350's have the timing mark at 2:00, while the 305 had it at 12:00. If you are using the wrong dampener with the wrong timing mark, it could cauise a very bad reading, but setting it with the plug not disconnected would also give bad readings. You can check by bringing the engine to TDC on the #1 cylinder, and seeing where the timing mark is in relation to the crank dampener mark. Should be at 0. Also, old dampeners do have a tendancy to Slip, causing the timing mark to move.

The Knock Detector is different from a 305 to a 350. It could be reading resonance in the engine as knocks, and retarding the ignition to try and get rid of them.

Fuel spilling over sounds like the float is stuck open. This would cause the car to run rich all the time, and may be part of the problem. This can be caused by a bad float, bad float setting, or by something stuck in the float opening. Easy enough to fix- buy a rebuild kit from NAPA and buy a float. $60, and about an hours worth of work or less. If you can pick up a copy of Doug Roe's book on Rochester carbs, it is a worthwhile investment. They are really a very good carb, when properly set up.

With just what I have read here, sounds like you need to get the timing set correctly, and then get the carb running properly. If you can't get the carb done yourself, and there are no others near you that REALLY know a CCC carb, you can buy a rebuilt online for about $300. With all that, you should have a good running engine. If you buy a rebuilt, buy one for a MonteCarlo SS, same year as yours. They have slightly better Secondary Rods ( DR), which will help with the 350. Also, if you can find a MCSS computer, they have the better spark tables ( PM me if really interested).