i don't think you'll gain much from a II to a III.
The 3 is more $$ and is made for big HP.
but i could be wrong... i'd ask brownie.

The work has been completed, I am real happy with the fine work my friend has done here. Tomorrow the area will be wet sanded and buffed before putting in the beauty rings.

eBay!!!! they will sell quick....

Heres a 18 second clip of my 540 idling with stainless marine 3's with 5" tails last summer without the mufflers,Smitty
http://www.youtube.com/watch?v=LMywg-P5Gos

Wow i did not expect this kind of responce from this topic

I love any info you can post on the gen 3's as I run them. Honestly I only bought them becauseI needed high flowing exhaust and a good friend of mine can get themat whoelsale cost.I hoped they made the same hp as good cmi's,now you've got me thinking of dynoing my motor with them when I get done freshening it this spring,it made 944 hp with cmi's on crocketts dyno so maybe it can actually make another 30-40 hp on dyno but boat won't go any faster because I been running them for 2 years already. Keep the info coming,I can't wait to hear a boat is a mph or 2 faster compared to cmi's in back to back testing,Smitty

nice work Albert

I can totally understand why Stainless Marine Gen 2s and CMI E-tops would flow vary similarly. I also can understand the larger volume of the Stainless Marine Gen 3s would be better than the other two on a supercharger engine or a high revving 500+cube engine like T-Mones.
But what about a true header with long runners like the CMIs on a Merc 525EFI. I would think the scaveging effects of a true long tube header would realy help a N/A engine like T-Mone's; maybe more than the larger volume of the Gen 3s???

Thank you Tom....

1 7/8 primarys tubes is the reason everyone beleives they slow you down