Sierra , Barr, osco manifolds

I have to replace the exhaust on a Mercruiser 165(actually a Chevy 250 for engine swap) . I used the old Osco exhaust to get another boat going. Did Osco go out of business or sell to someone else? Which manifolds and risers are better quality? Sierra or Barr?

Re: Sierra , Barr, osco manifolds

All about the same quality,dont use their gaskets,get OEM gaskets, you will be glad 6 months down the road.

Re: Sierra , Barr, osco manifolds

I just got a set of manifolds and risers from Osco. Made in USA and very nice quality. I ordered them with the quicksilver gaskets. I have no experience with the other brands but i have been told to steer clear of GLM.

Re: Sierra , Barr, osco manifolds

I bought a manifold from this company a couple of years ago. Good prices. (Manifold and associated gaskets only $399). If memory serves, it was an Osco manifold. Good quality.

Re: Sierra , Barr, osco manifolds

Made a phone call to Osco today whose rep informed me they discontinued manufacturing the Mercruiser 165 inline 6 manifold 3 years ago. The link in the last post is a Barr manifold. Not sure if Sierra or Barr is better as far as cracking is concerned. I like the price of the Barr better. Is there any problem using the straight 6 exhaust manifolds with closed cooling applications? Osco still has their old manifold listed even though it is nla. A note on the site says not for use with closed cooling applications. Did it make the manifolds more likely to crack or other issues? The Osco rep did not know. Before his time.

Re: Sierra , Barr, osco manifolds

I'm going to ad something from my very recent experience regarding the Osco/Barr debate. I purchased two Osco manifolds to replace my cracked OEM's. Not impressed at all. Poor casting, threaded ports for water lines and drain cocks were almost unusable without additional filing/thread cleaning. Huge voids in the casting where they just filled it in with a patch. On one manifold, there was a small chip in the metal right on the riser mating surface next to a water jacket. Definitely sub par quality. As luck would have it, one of my risers was bad, so I took the opportunity to give Barr a try. MUCH better quality...hands down! The casting looked as smooth and void free as OEM. No sharp edges, no slag, no pieces of machining leftovers jingling around inside. Threads accepted water ports/pipe plugs without a fuss. Mating surfaces were mirror smooth with no imperfections. I'm stuck with the Osco's and am never going to feel comfortable with them on my new engine; but they have to fail before you can return them for a refund. I think Barr is the way to go if you want to be as new to OEM quality as possible, without the OEM price. Just saying!