Intake manifold identification

[Tom L.]

I have a 1970 LS-5. Most everything with dates on the engine, including the original carb, is dated May of 1970. The intake manifold, however, appears to be dated October of 1968. At first, I assumed that someone had changed the manifold for some reason. But upon researching the casting numbers(3955287), it looks like this manifold was not made in 1968 or 1969. Rather, it was only made for 1970 390 hp cars and 1971 365hp cars. I have attached a picture of the numbers. Any ideas? Thanks.

[Michael W.]

Re: Intake manifold identification

The year in the casting date sure looks like a 9 to me...........

[Joe L.]

Re: Intake manifold identification

Tom------

The manifold is the correct one for your application. The date is J 27 9 which makes it October 27, 1969. Although this manifold was first used on Corvettes for the 1970 model year which didn't begin production until after 1-1-70, the production of other 1970 models began, as usual, in the fall of 1969. So, these manifolds were being cast well before October, 1969 for those other applications.

It's also very possible that this manifold is the one originally installed on your car, especially if it's an early 1970.

This is a manifold that I've always found a curiosity. It's CASTING number implies a late 1968 release for the 1969 model year. However, it's PART number, GM #3977608, implies a 1970 model year release. I expect that the casting was originally developed for some 1969 model year application and "put on hold". Then, it was "revived" for the 1970 model year with whatever machining was required for that use and assigned PART number 3977608.

It is also a manifold that deletes the carburetor "heat groove" present on all other 1969 Q-Jet manifolds. So, it's history may be somehow connected with the need to "rush to production" a manifold deleting this feature in connection with the massive 1969 recall of cars with "heat groove" manifolds.

[David B.]

Re: Intake manifold identification

Joe,

Can you expand on the recall of 69's with the heat groove? What did GM do about the problem?

Thanks,
Dave

[Joe L.]

Re: Intake manifold identification

Dave-----

I don't have any of the details; John Hinckley might, though. I know that I never received any sort of recall on my 1969 when it was new, either for the heat groove problem or the motor mounts.

[Tom L.]

Could it be original?

Is the October 27, 1969 manifold too old for my June 16, 1970 car, or could it be original given the labor strikes in late 69 and 70?

[Kevin M.]

Re: Could it be original?

Most likely a large original run and the inventory had not run out. There are only 1 or 2 date codes for the 67 A.I.R. SB manifolds both in 66.

Kevin

[Mark #28455]

Not likely

My March 1970 454 car has a Feb 1970 intake. That same casting was used on ALL oval port 396 and 454 engines, so it would have been a HUGE stockpile of October dated manifolds to last that long. That being said, could ONE manifold have sat in a back corner that long? SURE, but the NCRS won't have any reason to give you credit for the date.

Mark

[John H.]

Re: Could it be original?

Tom -

The NATIONAL strike (the only one that affected the engine plants) was from September to November, 1970, well after your car was built.

[Tom L.]

Thank you *NM*