Many truck supply stores carry stainless exhaust parts now. Just be careful on the pipe if the pipe you need will carry a lot of weight at a bend or connected to the turbo for that u need thicker wall that specialty steel supply stores carry.
The best place i ever found was a Wyerhouser(sp) pulp plant in Bellingham WA. they were slowly dismantling the plant and they had a scrap sales yard set up, i bought a 4" stainless elbow for my volvo exhaust there for $18 and a bucket full of 1/2 &3/4 stainless pipe fittings for 50 cents a piece. The guy that ran it told me to get anything i need soon cause as he said " when i retire this place is gone" sure enough 2 years later it was all gone. They hauled stainless and aluminum out of there by the 40 yard containers full all off to the junkyards for scrap. It killed me not being able to haul more stuff out of there.
Thanks for the replies. Mine is a fairly simple system and the system below the muffler to the turbo is still in perfect condition and mounted rock solid. Even the muffler is not in bad shape but the boat is being spruced up for a possible sale and the system could look better. A wire wheel might do the trick and new exhaust tape. This will be a spring project but I want to find the materials.
Steve, I regularly go to the scrap yards for my stainless and aluminum. Unfortunately, what used to be a DIY'ers gold mine is now being sold to the Chinese as fast as they get it. Pickings are slim.
I bought a 31' Ralph Stanley last year that I am in the process of converting to pleasure. It had a 292 Chevy engine with SS drytstack and muffler. I gave the engine to another fisherman, but he didn't need the stack. I'm switching it out to a diesel with wet exhaust and have no use for the stack. It is a little discolored, but otherwise in good shape. It is in North Caroilina...I'd be happy to ship it to you for the cost of shipping if you could use it. I can get you the exact dimensions, but it will be tomorrow. Let me know if you are interested...I can send you a photo and measurements....otherwise, it's going to the scrapyard soon.
Thanks Rick. I appreciate the thought. My stainless muffler is 15" in diameter by 36" long and the pipes are 6 3/4" OD with flanges to match the lower exhaust pipes. I will probably go with a new, custom bolt on muffler with a welded 90 degree exhaust stack.