Questions about LT-1 manifold painting and gasket t*******

[Patrick B.]

I used Felpro intake manifold gaskets, and I can't remember if GM gaskets covered as much of the area between the manifold and the valve covers as these gaskets. If not, do you try to trim the gaskets to expose more head? I see the word t r i m m i n g was censured!?

Also, I think the exposed head between the manifold and the valve cover and the exposed gasket were painted with aluminum paint. Is this correct? Actually, most of my manifold was covered with aluminum paint, not just the edges near the valve covers.

[Joe L.]

Re: Questions about LT-1 manifold painting and gasket t*******

I used Felpro intake manifold gaskets, and I can't remember if GM gaskets covered as much of the area between the manifold and the valve covers as these gaskets. If not, do you try to trim the gaskets to expose more head?

Also, I think the exposed head between the manifold and the valve cover and the exposed gasket were painted with aluminum paint. Is this correct? Actually, most of my manifold was covered with aluminum paint, not just the edges near the valve covers.

Patrick-------


The ORIGINAL GM gaskets did not have as much exposed material as shown in your photos. As I recall, later part-numbered, supercessive GM gaskets as well as many aftermarket did have exposed material much as you've pictured. Reproduction gasket sets available from Corvette parts vendors are of the correct configuration.

[Patrick H.]

Re: Questions about LT-1 manifold painting and gasket t*******

I used Felpro intake manifold gaskets, and I can't remember if GM gaskets covered as much of the area between the manifold and the valve covers as these gaskets. If not, do you try to trim the gaskets to expose more head?

Because of the metal layer usually sandwiched in the middle of the intake gasket I find attempts at cutting it to match an original to be difficult at best. Making it look factory is almost impossible. It's less work to remove the intake and replace the gasket.

[Joe L.]

Re: Questions about LT-1 manifold painting and gasket t*******

I used Felpro intake manifold gaskets, and I can't remember if GM gaskets covered as much of the area between the manifold and the valve covers as these gaskets. If not, do you try to trim the gaskets to expose more head? I see the word t r i m m i n g was censured!?

Also, I think the exposed head between the manifold and the valve cover and the exposed gasket were painted with aluminum paint. Is this correct? Actually, most of my manifold was covered with aluminum paint, not just the edges near the valve covers.

Patrick-------


These are the gaskets originally used on your engine. I believe the reproductions are pretty close; aftermarket and later GM SERVICE are not. In addition, original gaskets and the reproductions are "embossed" type gaskets. In my opinion (and the opinion of many others), these are the best sealing gaskets.

DSCN4253.jpgDSCN4254.jpgDSCN4255.jpgDSCN4256.jpgDSCN4258.jpg

[Patrick B.]

Re: Questions about LT-1 manifold painting and gasket t*******

Thanks for the pictures of the original gaskets. What about the aluminum paint on the bare surfaces of the heads and gaskets. Were the painted as I think they were from the factory?

[Ron G.]

Re: Questions about LT-1 manifold painting and gasket t*******

This is a subject that has been discus and covered numerous times. Instead of myself or others rewriting another post, and being repetitive, I would be happy to discuss it with you verbally if you want to reach out to my email and leave a phone number and I would be happy to explain the whole process to you. - Ron
RgodutiLT1@yahoo.com

[James G.]

Re: Questions about LT-1 manifold painting and gasket t*******

Here is a photo from the REVS institute which was taken during a roadtest of a 70 LT1. If you zoom in you can see the tab and also a line where silver paint is clearly on the head rails.
https://library.revsinstitute.org/chevrolet-lt-1-corvette-test/248673

[Mike E.]

Re: Questions about LT-1 manifold painting and gasket t*******

James, nice picture! On the left rear carb stud, is that a flanged nut with a washer below it holding the spring bracket and carb to the intake?

[Terry M.]

Re: Questions about LT-1 manifold painting and gasket t*******

One needs to remember this engine was i a very early car, perhaps even pre-production, which was prepared for Chevrolet Public Relations use. What we are looking at may or may not represent production models. Then there are the known, and in the 1970-1972 TIM&JG, differences between early and late engine builds,

My 170, engine build V0114CTU (I am sure this is not the first batch of 1970LT1 engines built) had the intake silver brush painted, Later engine builds were spray painted silver and the final rocker covers were not installed during orange painting. In my case no covers were on the engine as evidenced by a liberal coat of engine orange on the valve springs, rocker arms and other head components on both heads, in spite of the fact that in the lmid-1980s workers at Flint Engine told me the LT1 engines used "travel covers" to avoid the undercover paint that my engine has (or had the last time I had the rocker covers off decades ago.) As a testament to the quality of the engine orange paint, it was still on most of the undercover components after 50,000+ miles of sometimes vigorous driving.

Unforetold I can not tell you about the paint on the short part of exposed cylinder head adjacent to the intake manifold because the leaking gasoline from the Holley carburetor washed the silver paint off most of that area, and what paint is there may be the dried remains of the silver paint and gasoline. I wish the paint they brushed on the intake was as good as the engine orange, but it is not.

As an actional note my engine has hand-painted engine orange on the rear of the engine and no engine orange on the bell housing, except for a few errant brush strokes. It is not the usual engine orange over spray we see on most small blocks, and we see on the later LT1s. Without looking I believe all this is explained in the 1970-72 TIM&JG because that Judging Manual Coordinator is insistent on "if we know it, it goes in the Manual", And I agree with him.

As Ron G has said: This is an often-discussed issue (usually over adult beverages for some of us) and very lengthily to post.

AS a final note (I expect we all hope): Can I tell you all early 1970 LT1 engines are painted the way mine is? Absolutely bot. All I can tell you for sure is that all the early engines were NOT painted per TFP and mine is just one illustration of that. I believe the engine in that photograph is one other example. We all need to keep our image of TFP in mind that it is not always easy to predict what a given car may look like especially for early or late builds. This determination can tax a judge, and experience and studding a lot of mostly original cars is the only route to this skill. It is called experience. There is NO other route.