Exhaust conversion?

[pb]

I am in the midst of a complete engine rebuild of my 454 and want to convert from the Hardin log style to a center rise type specifically EMI Thunders. My concern is that my exhaust outlets are blow the swim platform just at water level. Will some type of transition elbow be required to get from the riser to the exhaust oulets. I plan on changing my exhast tips as well so would 12 degree tips be better suited for my application. Suggestions would be helpful.
Thanks
Paul

[Havasu Hangin']

Eddie has the "S" pipes:
http://www.eddiemarine.com/cart/Pictures/109_100.jpg
As well as the elbows (2 needed per side):
http://www.eddiemarine.com/cart/Pictures/109_101.jpg
I went with the elbows, as it was more flexible for my "under the swimstep" tips:
http://www.eddiemarine.com/cart/Pictures/100_03.jpg
I went with straight tips, as they lined up better with my bellows.
http://www.goldenplasma.f2s.com/forum/smilies/happy25.gif

[flat broke]

Pb,
The good news is that you might not have to buy the s-pipes. The bad news is you're going to have to do some measuring. On my Dana (orriginally logs) I went to Stainless Marine center rise manifolds and new tips. I went with the straight tips and only had to use standard 4"id hose (its cheaper at Teague than Eddie by a lot, but get your tips at Eddie cause their cheaper than Teague ;-) ) If I were in your shoes I would go ahead and get the new manifolds and do a mock up. Then take a long peice of coat hanger, welding rod, or whatever and mimick the path you want the tubing to go to the tips. If it looks like rubber will work (needs to be pretty straight and i'll tell you why in a second) measure and go buy a little bit more than you measured for. If you're going to have to have the S pipes done up, you can take your hanger jig to Eddie and see if their S pipes will get you to where you need to be. Conversely, you could also have a muffler guy bend up a custom set of aluminized pipes for you, but you'll need to stay after them with regular inspections. If you go with rubber, make sure that the exhast riser angle is mached by the rubber for a while before a bend. If the rubber is bent right near the end of the riser, the area at the outside of the apex will see more heat than usual and could fail over time. I know its a long winded post and i'd like to show you some pictures, but I have to get back to work.
Good luck,
Chris

[pb]

HH,
Are your exhaust outlet centerlines at the same elevation as the exhaust ports on your heads. I have the "F" pump so my horizontal distance from the riser outlet to the exhaust tip is limited since the engine sits further back. I really need to get the engine back in the boat and take some measurments. Do you happen to have a photo of our setup. Thanks for your input.
Paul

[Blown509Liberator]

In Our Baja TC with an F Pump I have Merc. center rise type Manifolds. I have Set it up with a rubber hose 1' off the riser to a SS wipe with a 45deg bend and ran it down 10" ( i think is was 10" I need to check) to a Rubber 30 deg RUBBER elbow on a straight 4" tips. It work great for me
MikeW

[pb]

Thanks for the info guys. Mike, I believe I am trying to accomplish exactly what you did. Any pictures would be great. Did you get your parts locally? Do you like the performance of the Merc. manifolds. I assume you have the Merc risers as well. Finally, do I need to change my valve covers to allow for the center rise configuration. I have standard M/T valve covers currently.
Paul

[Blown509Liberator]

They work better than the logs. With all the motor swaping and everything i was doing it was the best i could come up with for the Baja. My 502 with Lightning would pull 5000 but only about 4300 with the merc. But It still GPS'ed at 65 with the "a" Legend impeller. The SS 4" pipe i had. the Rubber elbow was from a plaese called Kendor Marine in Wi but i bet West Marine has them.
MikeW