70 LT1 N9 CARB. Heat shield

[Donn M.]

I have a 1970 LT1 California emissions (N9) car. The judging manual calls for a brushed aluminum heat shield between the carb. and intake (page #130). Several sources and a few NOS originals on E-bay identify as part # 3969835, which I do have and believe to be correct. Page #157 states the fuel line support bracket on LT1's is bolted to the right rear carburetor stud. The plate #3969835 cut out on the right side will not allow for the fuel line bracket.
I did have the car judged with the #3969385 heat plate , with the fuel line bracket off and received a deduction for no bracket.
I currently have a plate on the car that allows for the fuel line bracket, but received a deduction for it not being a #3969385.
Has anyone had this issue ? Does the Calif. car have a special bracket ? Should I re machine the correct bracket I have to allow for the fuel line ? Any advise would be appreciated. Donn

[Donn M.]

Re: 70 LT1 N9 CARB. Heat shield

Figured it out. In the very back of the 1970 AIM a page shows the heat shields. The '70 N9 uses a #3972156 heat plate and the #3969835 is for "LS7 and High performance". The one I have on the car is correct.

[Joe L.]

Re: 70 LT1 N9 CARB. Heat shield

Figured it out. In the very back of the 1970 AIM a page shows the heat shields. The '70 N9 uses a #3972156 heat plate and the #3969835 is for "LS7 and High performance". The one I have on the car is correct.

Donn------


How do you know the one you have is a 3972156 and can you post a photo of it?

[Donn M.]

Re: 70 LT1 N9 CARB. Heat shield

Can't do a photo unless I pull the carb, etc.. However, there is a photo of a used original #3972156 on ebay. That is the # that is specified and pictured for LT1 on page #399 of the 1970 AIM. I can see the # on mine back under the Holley. All the other ID stamping and profile are exactly the same and it is cut so the fuel line bracket can be attached to the rear carb. bolt. Appears they were also used on LT1 Camaros in '70.

[Joe L.]

Re: 70 LT1 N9 CARB. Heat shield

Can't do a photo unless I pull the carb, etc.. However, there is a photo of a used original #3972156 on ebay. That is the # that is specified and pictured for LT1 on page #399 of the 1970 AIM. I can see the # on mine back under the Holley. All the other ID stamping and profile are exactly the same and it is cut so the fuel line bracket can be attached to the rear carb. bolt. Appears they were also used on LT1 Camaros in '70.

Donn------


OK, very interesting. I think I'm finally starting to get this 1970 carb gasket thing figured out. As I mentioned in another post, the information for 1970 carb gaskets is somewhat sketchy. The AIM does not specify a gasket for 1970 LT-1 without EEC. P&A catalogs specify the GM #3881847.

For 1970 LT-1 with EEC, the AIM does specify the GM #3972156. It is shown in the AIM as a heat shield apparently with attached gasket. It is also cataloged for the application in the 1970 edition of the P&A catalog although the catalog also specifies the GM #3881847 and 3972192 for the 1970 LT-1 with EEC application. As I mentioned in a previous post, the GM #3972156 was discontinued in December, 1971 and replaced by the GM #3999198. The latter is a 1/4" thick, square bore gasket with no attached shield (NOS example I pictured in a post on another thread). So, I presumed the 3972156 was a similar part since I could not believe that GM would have replaced a heat shield type gasket with a 1/4" thick gasket with no shield. That has proven to be a false assumption on my part because that's exactly what they did. The only other square bore gasket with attached shield that existed at the time was the GM #3969385. It was scheduled for use on the still-born 1970 LS-7 with EEC but I could see no reason why it could not also have been used for 1970 LT-1 with EEC. Apparently, you discovered the reason.

Apparently, the 3972156 was a heat shield without attached gasket because I see no staple holes in the example on eBay. If so, it was likely used in combination with GM #3881847 and/or GM #3972192. The history of the 3881847 I previously described. The GM #3972192 was discontinued without supersession in January, 1970. However, whether or not the 3972156 had attached gaskets. it is definitely the piece used for 1970 LT-1 with EEC.

Please consider my previous statements that the gasket used for those application to be the 3969385 to be incorrect. So, I learned something here. I knew there had to be some reason I hang around this place.

[Donn M.]

Re: 70 LT1 N9 CARB. Heat shield

Joe, Thank you for the response, extensive information and the direction working through this one.
It was a good day for a good day! Donn