Building a 71 Cuda 340. Want to use 70 TA/AAR exhaust manifolds. Question is what system do I order? Are the header pipes the same for 70 AAR exhaust manifolds as the 340 4-Barrel? Thanks in advance for the assistance.

No such thing as AAR / T/A manifolds if that helps?

All 1970 340 Darts, Dusters, & 340 4-barrel Challengers & Cudas used the same type of exhaust manifolds.

(other than some older ones being used up from the prior model year)

All 1968-1970 exhaust manifolds interchange though.

71 is different on the passenger side. You can use any 68-70 340 exhaust manifolds from any body style, they are the same.

More info here: (Link to 340 Exhaust Manifolds)

Thanks for the quick response. My question was, however --Are the exhaust header pipes the same? In other words, are the exhaust pipes the same where they connect to the exhaust manifolds? Or, do both style exhaust manifolds use the same exhaust pipes/connections? Thanks in advance.

Is it true that in terms of flow restriction,
the driver’s side 1992-1993 Magnum V8 exhaust manifold shows more horsepower gain on a dyno,
but that the passenger side the 68-70 exhaust manifold out dynos the 1992-1993 Magnum V8 passenger side?

Maybe Steve Dulich found that result years ago?

The 340 headpipes are different between the 1970 and 1971 e body applications. See the following link.
http://www.accurateltd.com/70-74-E-Body-Small-Block-318340360-Complete-Exhaust-Systems-_p_239.html
Order the headpipes that correspond with the exhaust manifolds being used. The 1970 340 exhaust manifolds , (49,53 castings)
had welded hp flanges on the headpipes and used gaskets. The 1971 headpipes used a floating flange and ball joint connection arrangement that did not use a gasket between the manifolds (623,621 castings) and the headpipes. Hope this answers your question.

Why would that even matter? Aren't you going to have a muffler shop custom-bend a new system?

Thanks. That answers the question. I got it from here. Cheers...….