1970 LT-1 carburetor heat shield

[D S.]

A friend in California is having his 1970 LT-1 judged there in November. He says he believes his carburetor aluminum heat shield is missing. How many points would be deducted for not having it? He says his car is exempt from smog emissions in California and it has been since 1990. Does that have any bearing on the shield not having to be there?

Thanks,
Scott Sims
Texas Chapter

[Edward J.]

Re: 1970 LT-1 carburetor heat shield

Scott you can deduct 20 percent for completeness.You will have to look up the point value and where it is judged, carb.?

[Terry M.]

Re: 1970 LT-1 carburetor heat shield

Scott,

The Carburetor or intake manifold. Either would be the appropriate place for deduction IMO.

Unless his 1970 Corvette has the NA9 Emission System option, he does not need that shield. It was a part of that system in 1970. That system also consisted of a charcoal canister mounted low on the driver's side of the engine compartment, well hidden below the brake master cylinder. That system also consisted of a yellow label above the master cylinder, a number of vacuum hoses and a pipe along the driver's side frame rail to return vapors to the gas tank. There was also a vapor separator at the gas tank. It was the whole evaporative emissions system that became standard in 1971. You might direct him to the back part of the 1970 AIM where the NA9 system is illustrated.

[Daniel S.]

Re: 1970 LT-1 carburetor heat shield

I would imagine the heat shield itself stems from the same design used on the 1970 Z28 (LT1). It is nearly impossible to obtain.

[Terry M.]

Re: 1970 LT-1 carburetor heat shield

I would imagine the heat shield itself stems from the same design used on the 1970 Z28 (LT1). It is nearly impossible to obtain.

The one for the Z may well be the same part, even. I thought it was available in reproduction, although as usual there is a difference in them.

http://forums.corvetteforum.com/c3-general/2180834-70-lt1-heat-carb-heat.html

The above link has some inacurate info -- it was factory installed -- and is all dated information, but it may be useful.

http://www.jegs.com/i/Mr-Gasket/720/3710/10002/-1?parentProductId=743789

This is the one I called a reproduction above.

Google rules.

[D S.]

Re: 1970 LT-1 carburetor heat shield

Thanks to all who contributed to this. You guys are great to go into the additional information.

[Joe L.]

Re: 1970 LT-1 carburetor heat shield

I would imagine the heat shield itself stems from the same design used on the 1970 Z28 (LT1). It is nearly impossible to obtain.

Daniel-----


I believe the 1970 Z-28 shield with NA-9 was the same as 1970 Corvette with LT-1 and NA-9, GM #3972156. This piece was discontinued in December, 1971 and replaced by GM #3999198. The latter is 1/4" thick insulating gasket which has no shield. The 3999198 is very similar to the insulating gasket used for 1971 LT-1, GM #3989390 and, in fact, replaced it for SERVICE.

[D S.]

Re: 1970 LT-1 carburetor heat shield

The LT-1 wasn't sold new in California as I have learned today. It was sold new in Pennsylvania and the tank sticker shows that but the car is now in California so does the carburetor heat shield still need to be on it?

[Kenneth B.]

Re: 1970 LT-1 carburetor heat shield

The LT-1 wasn't sold new in California as I have learned today. It was sold new in Pennsylvania and the tank sticker shows that but the car is now in California so does the carburetor heat shield still need to be on it?

Not for NCRS judging & I think it would not have to meet Ca. smog testing because of age but maybe others know better.

[Joe L.]

Re: 1970 LT-1 carburetor heat shield

The LT-1 wasn't sold new in California as I have learned today. It was sold new in Pennsylvania and the tank sticker shows that but the car is now in California so does the carburetor heat shield still need to be on it?

Scott------

No, there is no retrofit requirement for 1970 model year cars. So, if a car was originally a non-California car and was brought into California with a certain number of miles on it (I forgot how many but it was not a lot---something like 5,000 or less), it was not required to have California emissions. Plus, a 1970 model year car is exempt from bi-annual smog inspection requirements (but is NOT exempt from the requirement that all original smog equipment be installed and that it meets exhaust emission standards).