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What carb number do you have?
1980 is not an ECM-controlled carb, but it does have electric choke.
If you don't have the right carb on the car, the concern would be that someone installed a commercially rebuilt carb, in which case you have much bigger problems than not having an electric choke...
What carb number do you have?
1980 is not an ECM-controlled carb, but it does have electric choke.
If you don't have the right carb on the car, the concern would be that someone installed a commercially rebuilt carb, in which case you have much bigger problems than not having an electric choke...
What carb number do you have?
1980 is not an ECM-controlled carb, but it does have electric choke.
If you don't have the right carb on the car, the concern would be that someone installed a commercially rebuilt carb, in which case you have much bigger problems than not having an electric choke...
Lars is referring to the fact that commercially rebuilt carburetors have a lousy reputation due to lack of consistency of the parts used in the rebuild. Scroll the post #5 in this link.
Your carb is not the right carb for your car. You have a 1978 carb for a 400 Heavy Duty Truck. Not a good carb selection for a passenger car or a Vette. It has a completely different choke system than what's required on your car, and cannot be retrofitted to the correct configuration (it's a "divorced choke" carb which is not compatible with your intake manifold). You need to find a correct model-series carb for your year car.
E-mail me for my paper about Commercially Rebuilt Q-Jets. Chances are good that's what you have. If it is, in addition to being a truck carb with the wrong choke system on it, the carb will have dozens of problems and issues that can be costly to correct.
Your carb is not the right carb for your car. You have a 1978 carb for a 400 Heavy Duty Truck. Not a good carb selection for a passenger car or a Vette. It has a completely different choke system than what's required on your car, and cannot be retrofitted to the correct configuration (it's a "divorced choke" carb which is not compatible with your intake manifold). You need to find a correct model-series carb for your year car.
E-mail me for my paper about Commercially Rebuilt Q-Jets. Chances are good that's what you have. If it is, in addition to being a truck carb with the wrong choke system on it, the carb will have dozens of problems and issues that can be costly to correct.
The carb you have is a model 4MV truck carb. You need a model M4M passenger car carb. The 2 carbs are completely different. You need the correct model-series carb for your car to have any hope of getting it running correctly. You cannot use what you have unless you do some real Bubba-mods to the system, and it will never be right.
Didn't the 1980 'California' cars come with the ECU/carb/dist system that had general release for Corvette in 1981? Could the OP's car be a CA vehicle?
Didn't the 1980 'California' cars come with the ECU/carb/dist system that had general release for Corvette in 1981? Could the OP's car be a CA vehicle?
Charley -
It's certainly possible that the car itself could be a CA car, in which case it would be a 305 car and not a 350. The OP states that it's a 350 car, which was not an available engine for California in 1980. The engine wiring harness would then have the pigtail connector for the electronic power piston setup, and the distributor would have an electrical connector replacing the vacuum advance unit. Either way, the carb is incorrect no matter what, and it's a divorced choke 1978 Heavy Duty truck carb that cannot be used if he intends to get the choke working on the stock manifold.
I have been in e-mail contact with the OP. For the benefit of those following this thread, and who may be interested in the answers, here is what I have written about the issue. If anyone is interested in the technical info papers that I e-mailed to the OP, just drop me an e-mail request for info:
"First, scrap the idea of getting a rebuilt carb from an auto parts store. Your'e going to end up with nothing but a pile of junk with a bunch of problems that will make your Corvette carb experience a truly lousy experience. The auto parts stores use commercial builders, and those builders make hack modifications to the carbs that destroy the carbs. See attached article for list of problems that will be on any "rebuilt" carb you buy. I make a bunch of money from the local auto parts store actually doing repair work on the rebuilt Q-Jets they sell to make them suitable for use, and the repair bill on the "new rebuilt" carbs typically runs over $400 each due to the amount of damaged and incorrect parts installed on the carbs being sold.
"First question is, are you trying to "restore" the car with a "numbers-matching" carb, or do you want to get it running well and set up with a carb that "appears" correct and that runs as it should? If you're shopping the auto parts stores, I assume you're just trying to find a suitable carb, since you'll never get the right date codes through those sources. If that's the case, you can use any 1976 - 1980 Chevy passenger car Q-Jet. The 1977 - 1979 carbs are plentiful and inexpensive, and they are all visually identical to your 1980 carb. The only thing you have to do is install the electric choke into the choke housing in place of the hot air choke (be sure to remove the choke cover gasket when you do this mod, or the choke will not have a path to ground and will be inoperable). This is a $50 conversion.
"What you need to do is start shopping eBay for an original, used carb that has not been commercially rebuilt or hacked. As noted, look for any Chevy passenger car carb from 1977 - 1980. Avoid the truck carbs and anything other than Chevy. Look for something dirty, but not rusty. If it's shiny and pretty, it's junk. Once you get a good core, get it correctly rebuilt. I can do that for you, or there are 2 other guys in addition to me in the business of doing nice work (Henry Olsen and Cliff Ruggles). I am attaching a bunch of info for you so you can make a good decision.
Through the help of another Forum member, we have tracked down a very nice, original 1977 Vette Q-Jet. That carb is being sent to me for a complete teardown, rebuild, setup and test, and I will be converting it to the 1980 electric choke configuration to make it identical to the OP's (Rod's) 1980 configuration requirement. Some very nice teamwork effort on the part of Forum members to get Rod set up with a correct carb system for his car!
Through the help of another Forum member, we have tracked down a very nice, original 1977 Vette Q-Jet. That carb is being sent to me for a complete teardown, rebuild, setup and test, and I will be converting it to the 1980 electric choke configuration to make it identical to the OP's (Rod's) 1980 configuration requirement. Some very nice teamwork effort on the part of Forum members to get Rod set up with a correct carb system for his car!
Lars
thanks to all involved its nice to be a forum member and to get a lot of information and help vettes rule
Just to add a little more info to this 1980 Q-Jet thread to those of you interested in the "correct" carb for the 1980 model year:
The 1980 carbs are visually identical to the 1976 - 1979 carbs, except they used an electric choke, replacing the hot air tube system used from 1975 - 1979. There are some differences in bowl vents (evaporative emissions), and there are differences in manual and auto trans carbs. The 1980 carbs were also leaned out a little at wide open throttle, so they need to be richened up a little if used on a modern performance application.
Here is a correct 1980 Q-Jet. This is a 7080228, which is an L82 High Performance 800 cfm carb:
Note the large nipple on the forward top edge of the float bowl for the charcoal canister:
This carb has provision on the throttle lever for TH350 auto trans kickdown cable and for the cruise control cable. Manual trans carbs have the lower part of the throttle lever cut off from the factory, and cannot be used with a TH350 auto trans without the kickdown cable attach point:
Note the choke housing is missing the hot air tube nipple, and the casting is not drilled for the nipple at all. When converting a hot air carb to electric, you need to cap off the hot air nipple to prevent the carb from drawing cold air into the housing - the cold air will delay or prevent full choke opening. It is also imperative that the gasket under the hot air choke cover be removed, since the electric choke grounds through the housing - if you install the gasket, the electric choke will not operate. Note the stock factory "L" shaped electrical connector - it requires the special mating "L" shaped plug on the wire harness. Aftermarket chokes are available with straight blade connectors:
Factory carbs had the cover attached with pop rivets so it could not be adjusted. When converting a hot air carb to electric using an aftermarket choke, it's a good idea to use screws so the choke duration can be adjusted and tailored to the application:
Rod (aka "rairh") has a "new" carb for his '80 on its way to him. Through the help of another Forum member Scott ("Cheeto"), we got our hands on a nice, original 1977 4-speed carb. The '77 manual tranny carb is not identical to a 1980 auto trans carb, so we had to make a few "conversions" to make things "right:"
Here is a 1977 Q-Jet. Note that the throttle lever for the manual tranny does not have the extension lever on the bottom for the TH350 kickdown cable, so the manual carbs cannot be used with a 350 automatic:
In this photo, you can see that the '77 does not have a bowl vent nipple in the float bowl for the charcoal canister evaporative system, and the choke housing has a nipple for the hot air tube system.. The rear of the airhorn also has a hot air tube nipple. The entire airhorn is a little different from the 1980 without provision for the bowl vent system:
Here is the carb after being converted into a "1980." The throttle lever has been changed to an automatic lever, including addition of the cruise control stud. The airhorn has been changed to the 1980 style airhorn, and the float bowl has been drilled and fitted with the bowl vent nipple. The choke housing has been modified to delete and plug the hot air tube system, and the correct electric choke with the "L" spade connector has been installed. This thing will run really nicely on the 1980. Compare this carb to the "real" 1980 carb shown in my previous post and you'd be hard pressed to tell the difference:
04-16-2018, 03:49 PM
