LS6 Intake Manifolds how to tell original vs. reproduction

[Paul S.]

Hi, I just purchased Intake Mainfolds for an LS6 #3963569 I was told they are original been in his garage for 20 years. How do I tell that it is an original and not a reproduction? Are the firing order numbers in different places on the back of the manifold?

[Joe L.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Hi, I just purchased Intake Mainfolds for an LS6 #3963569 I was told they are original been in his garage for 20 years. How do I tell that they are and not a reproduction? Are the numbers in different places the manifolds?

Paul-----


While this manifold has been reproduced, the reproductions are FAR more rare than used originals. In fact, I've only seen one reproduction EVER. However, I've seen quite a few originals and have purchased about 5 or 6 of these over the years which I have stashed away.

The dates on these manifolds are under the heat shield, so it has to be removed in order to see it. I wouldn't bother.

1970 versions of this manifold which were used on L-78 Chevelles, Novas and Camaros as well as LS-6 Chevelles did not have large cylinder numbers cast into the top of the ends of the runners. The 1971 version, used only on LS-6 Corvettes, did have the cylinder numbers cast on the top of the runners.

[Paul S.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Are the firing order numbers next to the heat shield in a straight line or are they sprawled out and quite large across the bottom?

[Joe L.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Are the firing order numbers next to the heat shield in a straight line or are they sprawled out and quite large across the bottom?

Paul-----


There are no firing order numbers cast on these manifolds. If there were firing order numbers, they sure wouldn't be on the underside of the manifold; they wouldn't do anyone any good there, at all. Plus, the numbers you are referring to are "1 2 3 4 5 6 7 8 9" which sure isn't the firing order of these engines.

In any event, the numbers you are referring to are on one end of the bottom of the manifold and I suppose one could say they are "sprawled out". I have no idea what the significance of these numbers is. However, we can say, for sure, it's not firing order.

[Paul S.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Thanks Joe---

I have seen the " 1 2 3 4 5 6" numbers sprawled out on the bottom. But I need to know if my manifold that has the numbers stamped alongside the heat shield and more contained and in single file (not sprawled) is an original or reproduction. In other words is that how you tell the difference from an original or reproduction. I know you said the reproductions are rare but I am worried now I might have one.

[Edward C.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

I am not an expert on this but wouldn't the origional have the Winters snowflake and the part number match the specification of the origional?

[Paul S.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Ed,
Yes, I have all that. The only thing different that I noticed from other manifolds I have seen is where those numbers are located and the way they are stamped (sprawled vs. tight in line). Does it matter?

[Edward C.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Sorry Paul I do not know. Ed

[Patrick H.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Paul,

How about posting some photos so that others can evaluate the manifold?

Just a thought.

Patrick

[Warren F.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Paul,

The earliest dated 3963569 manifold I know of with the numbered runners is with a June date code. All original 1971 LS6 Corvettes have been seen with only the unnumbered manifolds.
The numbered runner manifolds are service dated components.

[Joe L.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Paul,

All original 1971 LS6 Corvettes have been seen with only the unnumbered manifolds.

Warren-----


I was not aware of that but I checked it out and it appears that's correct. These must have been the only 1971 intake manifolds without the numbers, though. As far as I know, all the others had them, including LT-1.

[Warren F.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Joe,

That's correct.

[Paul S.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Thanks, everyone. It confirms some of the information I found also. Here are some pictures of the manifold. I tried to show where the number sequence is different than what I have seen. Paul

[Tom M.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

I have seen a lot of re-pop parts in my day , but not a LS6 vette intake

[Dick W.]

Re: LS6 Intake Manifolds how to tell original vs. reproduction

Just a later service replacement intake. Ya gotta remember that the LS-6 hood was so low that they could not use some of the better intakes, i.e. L/88, 425, etc. A good intake and a good set of headers should really bring one of those motors to life.