gnorthga

by the way which props u running and do u have shorties

t500hps

If you have a 35 Fountain then we have completely different hulls. I have a 2002 382 Formula, as you know they are considerably slower than your fountain. Everything I've read suggests shorties and extension boxes produce very minimal gains on this hull (and the cost isn't worth it to me). I'm running regular length XR's w/o boxes.

While we "only" made 630 hp at 5,200.......they made 700 tq at 4,300. My goal was cruise speed and the high tq number was perfect. But always wanting more!

With 500EFI's the boat comes stock with 28 Bravos. I have several props that all provide good cruise speed and need a set of "top-end" props. Currently running 28 MAX that are full 15 5/8 and labbed (still have the diffuser ring). I also have a set of 30 MAX that are 15 1/8 and thinned at the leading edge but not truely "labbed". These perform nearly identical to the 28 MAX's and have always been within 100 rpms and .5 mph of the 28's (WOT numbers were 0.1 different). With 1/2 fuel and all gear at 3,500 rpms I'm seeing anywhere from 54 to 58 GPS. WOT has been 5,300 at about 83 with either of these props. The fastest props I ran were labbed 30 Bravos, these turn 5,600 at about 86.

How's your setup run? Props etc. In a 35 I suspect your over the century mark!!!!

gnorthga

I run 6 blade with a long defuser ring 32x15 runs a trun 97 miles but I would be more than happy to hang out with u and your family and have a beer on any lake we got a poker run on chicamauga lake in may would u guys please come

bcarpman

I'd love to hear more about what you did!!! Where did you cut the divider? Did you stay with the o-rings, or just make gaskets? What did you do to the lower?

bcarpman

I can almost garrantee the plenum is too small for peak power. I've seen bigger plenums on small blocks. The only thing you lose with a bigger plenum is throttle response, but even that isn't much of an issue till you get really big.

Like I said earlier, the only things that stops me from making a new plenum for it is not knowing what I'd really gain from all the work, and the look: everyone recognizes the HP500 manifold, and I know whatever I came up with would be a lot less "slick" looking.

It would be pretty easy to impove on this plenum: Just start with a 1/4 inch base plate cut bigger than the lower runners on all sides (you want the runner to be able to breath on all four sides). Add another 1/4 inch plate around the top of the runners to provide a generous 180 deg. radius at the top of each runner. Then weld up a box around the plate. Wouldn't need to be any thicker than the stock plenum, as the increased length and width would provide the extra volume.

Of course then it would just look like a big box on top of the engine. Something about the look of those runners sticking out the side of the plennum that just looks mean!