70 L46, what type of carb do I have?

[Mike F.]

This all started because I wanted to install the ECS solenoid. What type of carb do I have?

I have a 70 (May 70) L46, 4spd with ECS, carb # 7040507 3529 (Dec. 69?)

Currently the car has a vacuum line going from the distributor to the drivers side of the carb. (Distributor, pic 1)

Driver side view (pic 2) - You can see where the distributor vacuum line attaches to the carb. The forward top of my carb seems to be missing a metal box that is installed on the carb in Dobbins book. (pic 7 & 8, Vette Vues Fact Book M.F. Dobins)

Front view (pic 3) - You can see two vacuum ports, driver side with current distibutor line and passenger side with red cap (ECS should go here).

Passenger side view (pic 4)

Rear view (pic 5)

ECS installed view (pic 6) - With the ECS installed what becomes of the drivers side vacuum port?

The carb certainly looks different compared to the pics in Dobbins book (if they are the correct pics?).

The numbers seem to match the TIM&JG, but the carb doesn't seem to fit the numbers.

What do I have? Can I simply plug the drivers side vacuum port with the ECS hooked up?

Any help appreciated.

[Mike F.]

Re: 70 L46, what type of carb do I have?

More pics.....

[Clem Z.]

Re: 70 L46, what type of carb do I have?

This all started because I wanted to install the ECS solenoid. What type of carb do I have?

I have a 70 (May 70) L46, 4spd with ECS, carb # 7040507 3529 (Dec. 69?)

Currently the car has a vacuum line going from the distributor to the drivers side of the carb. (Distributor, pic 1)

Driver side view (pic 2) - You can see where the distributor vacuum line attaches to the carb. The forward top of my carb seems to be missing a metal box that is installed on the carb in Dobbins book. (pic 7 & 8, Vette Vues Fact Book M.F. Dobins)

Front view (pic 3) - You can see two vacuum ports, driver side with current distibutor line and passenger side with red cap (ECS should go here).

Passenger side view (pic 4)

Rear view (pic 5)

ECS installed view (pic 6) - With the ECS installed what becomes of the drivers side vacuum port?

The carb certainly looks different compared to the pics in Dobbins book (if they are the correct pics?).

The numbers seem to match the TIM&JG, but the carb doesn't seem to fit the numbers.

What do I have? Can I simply plug the drivers side vacuum port with the ECS hooked up?

Any help appreciated.

you have a quadrajet carb for a 1970 350 calif corvette. is your corvette a calif car ??

[Joe L.]

Re: 70 L46, what type of carb do I have?

This all started because I wanted to install the ECS solenoid. What type of carb do I have?

I have a 70 (May 70) L46, 4spd with ECS, carb # 7040507 3529 (Dec. 69?)

Currently the car has a vacuum line going from the distributor to the drivers side of the carb. (Distributor, pic 1)

Driver side view (pic 2) - You can see where the distributor vacuum line attaches to the carb. The forward top of my carb seems to be missing a metal box that is installed on the carb in Dobbins book. (pic 7 & 8, Vette Vues Fact Book M.F. Dobins)

Front view (pic 3) - You can see two vacuum ports, driver side with current distibutor line and passenger side with red cap (ECS should go here).

Passenger side view (pic 4)

Rear view (pic 5)

ECS installed view (pic 6) - With the ECS installed what becomes of the drivers side vacuum port?

The carb certainly looks different compared to the pics in Dobbins book (if they are the correct pics?).

The numbers seem to match the TIM&JG, but the carb doesn't seem to fit the numbers.

What do I have? Can I simply plug the drivers side vacuum port with the ECS hooked up?

Any help appreciated.

Mike------


As clem mentions, the carb you have is for an original NA-9 optioned car. This option was a required option for delivery of a 1970 model Corvette in California. I don't know if it could be ordered for delivery into other states, but it was certainly not required for other states. Most likely, it was not orderable except for California-delivered cars.

The NA-9 option included EEC (evaporative emissions control) provisions. That's why the carb does not have the fuel bowl vent and cover as you have pointed out in the photos from Vette Vues. This style fuel bowl vent and cover was used only on non-California 1970 Q-Jets (as well as earlier Q-Jets).

With the NA-9 carburetor the vacuum port on the lower driver side of the fuel bowl is used for the vacuum source for the evaporative emissions control system. On your car, the evaporative emissions control system may have been removed, wholly or partially. A diagram of the system can be found in the NA-9 option section of your AIM.

By the way, this carburetor is EXTREMELY RARE. I would not let it out of my sight.

[Mike F.]

Re: 70 L46, what type of carb do I have?

you have a quadrajet carb for a 1970 350 calif corvette. is your corvette a calif car ??

I'm not sure yet, the paper work for initial delivery is in the mail.

If it is a California car, should the L46 have A.I.R.?

[Joe L.]

Re: 70 L46, what type of carb do I have?

I'm not sure yet, the paper work for initial delivery is in the mail.

If it is a California car, should the L46 have A.I.R.?

Mike------


No. The only Corvette engine that originally was equipped with AIR for 1970 was the LT-1, whether for California or not. The 1970 L-46 was NOT equipped with AIR, either for California or for other states.

[Terry M.]

Re: 70 L46, what type of carb do I have?

Mike------


As clem mentions, the carb you have is for an original NA-9 optioned car. This option was a required option for delivery of a 1970 model Corvette in California. I don't know if it could be ordered for delivery into other states, but it was certainly not required for other states. Most likely, it was not orderable except for California-delivered cars.

When I was doing the research for the 1993 version of the 1970-72 TIM&JG (actually that version had a different title, but let's not get distracted by that) I found a number of NA9 equipped 1970 Corvettes that were not originally delivered to California. Now whether that option was ordered for them or "forced" on them I was not able to find out. There were even one or two that had incomplete NA9 installations in otherwise apparently rather original cars. Sadly those cars were no longer in the hands of the original owners, so no definitive conclusion could be made.

[Patrick H.]

Re: 70 L46, what type of carb do I have?

Joe,

If you get a chance, check how long this carb was available in service.

Patrick

[Joe L.]

Re: 70 L46, what type of carb do I have?

Joe,

If you get a chance, check how long this carb was available in service.

Patrick

Patrick------


I cannot find any information indicating that the GM #7040507 or any other of the 1970 EEC carburetors were EVER available in SERVICE through the GM parts system. This includes their being available under any other on-box part number (i.e. a 7040507 carburetor in a box under a different part number because of other parts included with the unit).

However, it is possible that such carburetors were available through the Delco parts system. I have no reference information for that, though.

[Patrick H.]

Re: 70 L46, what type of carb do I have?

Patrick------


I cannot find any information indicating that the GM #7040507 or any other of the 1970 EEC carburetors were EVER available in SERVICE through the GM parts system. This includes their being available under any other on-box part number (i.e. a 7040507 carburetor in a box under a different part number because of other parts included with the unit).

However, it is possible that such carburetors were available through the Delco parts system. I have no reference information for that, though.

I have a 07040507 carb, so I wondered if a 7040507 was available for a while until they started adding the "0" later.

Patrick

[Clem Z.]

Re: 70 L46, what type of carb do I have?

the only different parts listed between a 207 and a 507 are the float bowl and the throttle body. no internal parts are different

[Joe L.]

Re: 70 L46, what type of carb do I have?

I have a 07040507 carb, so I wondered if a 7040507 was available for a while until they started adding the "0" later.

Patrick

Patrick------


What's the date on this carburetor?

[Mike F.]

Re: 70 L46, what type of carb do I have?

Found out my car was delivered to Dailey Chevrolet, Erie, PA.

Trying to track down past owners to see if carb is original or replaced.

Mike

[Jack H.]

Re: 70 L46, what type of carb do I have?

"I have a 07040507 carb, so I wondered if a 7040507 was available for a while until they started adding the "0" later."

Remember there were two suppliers of QJet then, Pat...Rochester and Carter. The leading zero issue might be a startup or 'hiccup' issue with just one of the two suppliers...

While it might seem 'neat' to have a rather rare part like NA9 California emissions, this might be to Shark cars what discovering this/that C1 car was originally equipped with a power top! If I remember correctly, California represented roughly 15% of the Corvette consuming market.

But, in an interesting cocktail discussion with Terry McManmon, he revealed that he could recollect something like TEN cars showing up for Flight Judging with the NA9 option on them. Methinks that's because prior owners discarded those 'rare' parts over the years and it's a PITA to try and properly restore one of the critters today...

[Patrick H.]

Re: 70 L46, what type of carb do I have?

"I have a 07040507 carb, so I wondered if a 7040507 was available for a while until they started adding the "0" later."

Remember there were two suppliers of QJet then, Pat...Rochester and Carter. The leading zero issue might be a startup or 'hiccup' issue with just one of the two suppliers...

Jack,

"0" prefixes show up in the later 1970s on service replacement carbs. Mine is, without a doubt, a service replacement item.

Patrick