correct exhaust manifolds

have a 71 340 duster which I believe is has all correct engine components.
my question is this....when looking at other 71 340 dusters most have the early style exhaust manifolds(68-70)
door sticker build date is 12-70
was told that early builds had the 68 style and at some time they changed over to the log style
so how do I tell which ones are correct for me as I need to replace the head pipes soon.

Thanks for all replies
Bennoel

No 71 340 A-Body's should have the 68-70 style exhaust manifolds.

That's exactly what I always thought.
After looking at several examples at MCACN I saw at least two 71 dusters with the early manifolds.
Asked the owners and they told me that they came like that. So now I don't know if it's a early production thing ?????
And also one 71 demon with the early manifolds as well.

Thanks
Bennoel

The drivers side is the 68-70 style.

The passenger side is the log style in 71

All regular production 1971 A-body 340's had the same manifolds, early or not.

I did mean to say the passenger side is log style, but you already knew that I am pretty sure.

Maybe this will help. These are 68-70 (pair) there are two versions of the drivers side, early and late. Both versions share the same casting numbers but the early versions have the casting numbers cast in the typical protruding fashion, later versions where the casting number was debossed (looks pressed into the cast iron surface, not protruding). The later versions started showing up sometime during the 1970 model year. The pair shown here are early versions

These are the 71 A-body Manifolds (Drivers side is the same used from 68-70, Pass side is new in 71 and fits 340 A-body, 340 E-body, and C-body 360 cars)

These are 71 E-body 340 manifolds

Great info. thanks for posting.

Anyone know the reasoning as to why two different heat riser counterweights were used on the 68-70 340 manifolds.
The thin ones shown in Scotts pictures and the thicker one, can both be found on assembly line 68-70 340 manifolds.
Could it be early verses later 68-70 manifold as I believe the thinner ones are more commonly seen.

so first of all thanks to everyone for the info. after searching for the correct manifolds I have found two pass side manifolds which I'm told are correct for 71 340 a body. they both end in a 3 not 6. in other words I'm told 3418623 is correct. so maybe both are correct, one early one late ?????