I have a 81 Spectra 20 With a 260 Mercruiser. I am going to convert the exhaust, from the log style to center rise and thru hull exhaust. I will be getting rid of the Y pipe and installing a block off plate.
 Do I have to buy a different Tstat housing, or can I use my existing housing?
 Is there any thing else that won't work with the conversion, like accessory brackets and such? thanks........Hal

Sounds like you are going to go through hull...This is a great mod. You should be OK on this swap because everything on your current set up (providing it is stock) bolts to the intake manifold and transom bracket. If you have Thunderbolt ignition you may need to make a bracket for the module.

If you are pulling the engine anyways, make sure to align the engine with a pilot tool (a lot like a large clutch pilot tool).

When I do the though transom set ups I always like to use pipe from the outlets of the manifolds to the through hulls, not only does it sound better, it will allow you to use regular exhaust hose instead of the wire reinforced stuff. Copper is what I use, works great and lasts forever, if you powder coat it they will be really awesome looking for a long time.

Good luck, should work out great.

GT

I got the engine back in the boat and I have isues and questions. Where it sits the risers come in.in a position that will not work. The riser and powersteering unit are interfearing with each other.
What I need to do is have the tips come thru below the power steering unit and in order to do that i will have to use an S pipe and hose, and inorder to do that the risers need to be shorter. My question, is there any reason that I could not cut the risers shorter? I really hate to cut them, but its what I have and I dont want to spend the money to just buy shorter ones.
 Also I had to switch T-stat housings and the original water inlet hose came in on the starboard side, but the new housing has the inlet on the port side. I need to rout the hose from the tramsomplate on the starboard to the port side. Can I route the hose and cross under the oilpan to the port and use the molded hose for the port side conection?
 Here are a couple pics of the issues.






 

Time to go hydro external steering.... Got another $5000 you don't need?   


In all seriousness, you can cut them down. try to leave as much length as you can and check into elbows meant for what you are trying to do.

Good luck. Looks bitchen

try posting a WTB ad on rd, powerboats, and offshoreonly... offshore seems to have a LOT of center rise stuff floating around. 

Looks awesome I want to do the same thing so I don't have to pull the exhaust just to change the oil.

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