This is a really good topic, really!
Thanks Chris for bringing it up! Hopefully it gets some love and views from the newbs.
Any other engine, and even the 460 in a vehicle, an intake change is a noticeable improvement. The Marine 460, however, is another animal. Other than weight savings, "upgrading" from the cast iron Cobra Jet intake on them is a pretty tall order.
As far as dual planes go, the Weiand Stealth is the shizzle. Not that the others aren't good, but they won't do anything the original manifold didn't do and just not worth the trouble.
Jet Boats, for the most part, desire a single plane. The 460 is a unique challenge there in finding one that outperforms the stock, cast iron, 40 year old dual plane that Ford put on them. Upgrading cams quantifies the problem.
I really like B-Rads setup! But there's a lot of absolute junk out there. For instance, the original "Torker 460" is a piece of scrap aluminum, even in a street vehicle. Bigger port sizes on a small block Chevy intake and this is an engine that needs to breath. Ralph's results with his "Torker 2" are not surprising, but I've never dealt with one of those, personally. The "Performer" and "Performer RPM Air Gap" are good, but really offer nothing that the factory cast iron unit didn't deliver.
Now, on a street vehicle or 4x4, these may be a significant advantage over factory. But on a Jet Boat, not so much.
Paul would be the definitive authority with actual dyno info, but my "seat of the pants" reaction is that the only readily available "upgrades" out there would be the Eddie "Victor", the Trick Flow units, or the Ford Racing ones. All are single plane, and very dependant on porting, port matching, and cam selection, but that's the limited catalog I'd be looking at.
Just my .02, But Jon Kaase's ENTIRE 460 catalog should tell you something.........
http://www.jonkaaseracingengines.com/products/intakes.htmlRay
