Just ordered a new tti exhaust for my cuda and I needed to get the part numbers off of the manifolds and this is what I pulled off of them this morning. Some of the numbers were hard to make out so I just wanted you guys to correct me if I read them wrong. Drivers side 3751094-4 passenger side 3418623-1. Thanks for any help .

Looks like I have the wrong one on the drivers side? That funny my brothers was saying that I needed the one that shoots up but my bronze 71 cuda has the same one on the drivers side. Any one know what the one I have on it goes to?

Picture of the one on my bronze 71 340 cuda.

Those both look right for 71 340 e body but I also have the same numbers as Dan listed in my research paperwork for my 71 challenger.

part no. VS. cast no.

LH 1971 B & E-body 340 C-body 360
3418620 VS. 3418621
RH 1971-'73 A B & E-body 340 C-body 360
3418624 VS. 3418623

LH 1973-'74 B C & E-body 340/360
3751083 VS. ???????

WAG ^ this unknown casting number part is what you have

Thanks so much for your help

Here's an original pair off of an early 1970 production 340 E-body

2 drivers side numbers

Scott , The manifolds you have pictured above may be from an early 1971 340 e-body but not an early 1970. Some early 1971 340 e-bodies have been known to have the 49-53(last 2 digits of the casting numbers) castings as the 1970 models.
The 49-53 castings were the same as the 68-70 A-body
340 manifolds as most probably know.

Sorry, that was a typo, they are from a 71 car (71 Challenger in this case) SPD was September 18, 1970 so obviously castings dated August of 1970 would not have gone onto a 70 model year car since 70 production was over with by then.

Quote:

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Some early 1971 340 e-bodies have been known to have the 49-53(last 2 digits of the casting numbers) castings as the 1970 models.

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I have never seen a (proven) original 71 model year E-body with 1970 manifolds, do you know of a documented exception?

The only documentation we have is when a customer calls for an exhaust system and claims the 70 manifolds were on the 71 car when bought new.
Also probably for the same reason that 1971 models are supposed to have only one exhaust hanger floor pan bracket(left side) but some have two like 1970 models.Learned a long time ago "never say never" with Mopar. Same issue with some early 1970 B-body cars having 1969 exhaust manifolds. An old Chrysler assembly worker told me one time that he remembers using up previous years inventory before installing the new inventory. Makes good business sense but who really knows. Documentation is great most of the time but in the real world sometimes is not reality.

Right Tom, never say never with Mopar, I agree. That's a pretty significant exception, which is why I was asking if you had any solid evidence to the positive on that one, especially since a lot of guys prefer the cooler looking 70 style manifolds and "wish" they came on thier 71 cars as opposed to the log style. I could see a pre production car (pilot car, etc.) possibly coming through with the 70 style, those cars often had prior year parts on them, but on a regular production example I'd need to see it to believe it.

FWIW I had an early production '71 340 Challenger - 802 SPD, 100139 - it had the log style manifolds.

It did have other less-obvious '70 parts such as inner fenders, front fenders etc.