thsorens

I am working on an 84 Mercruiser V8. I stroked it to a 383 last year am running 10:1 compression with Sportsman II heads and a fairly big Comp cam (don't have the numbers on me). anyway, I want to hear it! I have the factory center rise manifolds and 3" Y pipe. I purchased a pair of Corsa's diverters, but can't really figure out what else I need. I'm pretty sure I need to change my y-pipe out to the newer style 4" pipe (which means pulling the engine, but whats 1 more time). Do I also need different risers? Which ones? What year boat do I need the Y-Pipe off of? My buddy has some 4" tips for me and probably some 4" hose. I'm not really looking as much for performance as just sound, and since I pull the kids on tubes alot, I definately want the diverters so I can turn the noise off. Any help will be appreciated.
Thanks

Pat McPherson

You should not have to change the Y pipe.
There is a molded rubber coupling/reducer available to go from the diverters to the Y pipe.
I had them on a 4" risers and elbow to the Y-pipe before I went to through hull exhaust. I may still have them, I'll check, if I do there yours for the cost of shipping...
You will also need the 4" risers if you don't already have them...

thsorens

That would be awesome thanks! Let me know, I can paypal you the shipping. Not pulling the engine again would be a bonus! With my current risers which I'm pretty sure are 3", the diverters angle down so much that there wouldn't be room for a 4" to 3" coupler between the diverter and the y-pipe, but I'll bet a 4" riser would straighten that out. Do I just get a stock 4" riser off of a newer boat or do I need some aftermarket riser?
Thanks again!
Tom

Big Block Billy

If you do pull the engine, try to get the newer y-pipe , it is bigger, and has better flappers in it. They are all over the place and can be had new for $100. Yup You need the 4" elbows. Try spots1994's ebay auctions, he has new merc ones for $108.00 ea. I would advise using the New Merc ones because they are galvanized and powder coated and are way better than aftermarket crap. BBB

pullmytrigger

I did that swap out last year......smallblocks......changed out the stock Merc Silent Choice to Corsa Electric......had to cut the stainless diverter pipe in two places (each diverter) to get them to fit.......didnt know there were two different size y pipes......I wouldnt pay $200 for new risers..... Id put my money into some new Revolution Marine manifolds for a grand and have all new 4" stuff.....take 100lbs off the back of the boat and more performance..........your 1984 exhaust is probably ready to go (fail internally) and lunch your nice engine.......doug