My Manifold is rusty, like flaking rusty- I am replaced the exhaust, deleted the cat, and am now replacing the down-pipe; I'll take it to an exhaust shop to replace the manifold studs- but should I replace the manifold as long as it works or just let rusty be? I'm finding it hard to locate a B23 specific exhaust manifold or header for replacement, if anyone has a decent one I'm in the market.

I have never seen or heard of an exhaust manifold/header rusting to the point of failure.
If you are interested, I have a B23 manifold,with minimal rust.let me know if you are interested.
In fact, I have an entire B23 engine availiable,in good shape.Need parts?

The plot thickens.... I went to two mechanics today who do custom exhaust and engine work, and neither wanted anything to do with my rusty manifold with rusty studs. Also- the previous owner put a new custom exhaust with a cat delete, and I was told exhaust shops could not legally work on my system w/o adding a cat back in- which I have no interest in doing. Now it looks like the easiest route would be doing it myself and replacing the head and manifold?

If you are taking it to an exhaust shop, get their opinion on whether or not it is still serviceable - they see a dozen a day and should know.
--
Bob: son's XC70, dtr's '94-940, my 81GL, 83-DL, 89-745(V8) and 98-S90. Also 77-MGB and some old motorcycles.

I have a good exhaust manifold from a '93 245 (Oldsmobile V8 now lives in the engine bay). It's yours for $25 plus shipping. Get in touch---fastforwardphoto(AT)yahoo(DOT)com---or call six-three-one-968-8933. -- Dave