2951123 manifold on duster?

[71_Duster]

I looked up and I believe it’s for a 68-69 dart 318. However I have a 340 from a 68’ going Into a stock 71’ 340 duster. Are the 318 manifold less restrictive than a 340 manifold? Would it interfere? I do believe it does have power steering. Helping project for my brother.

 

[Professor Fate]

They'll physically fit the 340, but 318 exhaust manifolds have smaller ports and outlets (i.e. more restrictive) than 340 manifolds.
https://www.bing.com/ck/a?!&&p=4574...21vcGFyX2V4aGF1c3QtcGRmLjE3MTQ2NjcyNDYv&ntb=1