I'm taking out the cat-ridden exhaust manifolds on my '75 450SL and replacing them with non-cat manifolds. Would using an early style manifold ('72 280SE 4.5 or '72-73 450SL) make an difference than say if I used an later model manifold, such as '77 to '79?

I have the opportunity to grab a later pair that is without the cats, but if an early model manifold would suit me better, I'd like to know.

Thanks!

David