Are they all interchangeable, more spicifucally exhaust manifolds, can I put an rs turbo manifold on an 1800 sierra cvh? Are the ports the same as bolt patterns look similar cheers

Yes, I used a Westfield 1.6 CVH exhaust on my 1.8 cvh with no modification, and subsequently on my Zetec with a bit of modification to bolt holes.

Not sure about inlet manifolds.
Stu

[Edited on 10/11/15 by SJ]