Y'all just might want to do a little research before you go any further on Delta Performance.
Google, BoatDiesel, Hull Truth for starters.

http://www.ripoffreport.com/fishing/...greg-cb585.htm
http://delta-performance-marine.piss...019269135.html
http://www.shamscam.com/delta-perfor...ine-a2802.html

Be careful out there amongst the English....

I think you on the right track, and I believe your performance estimate is conservative.

That said, I know somewhat less than zero abt Aronow Cats, but hp is hp, and if they cruise at 70 with 500 gas hp a side, they will cruise 70 with 500 diesel hp a side.

Talk to Rik at Arneson. He has helped with several diesel performance boats.

If you get the right wheels, you may not need a 2-sp tranny. Skater's Diesel 399 Vee has two bone-stock Cummins 6.7 and single ratio ZF and cruises easily at +70.

Pat Weismann makes 6 & 8sp automatic transmissions, too, that fit sweetly with diesels and can drain every drop of power from the engines.

Bob

spoke to the guy today that built a couple new ones 400 hp mans top end 65 mph cruise at 98% so it looks like its possible this was a single speed overdriven tranny on a 1.25 arneson 8 I have been in the silver skater v it is spectacular, but unfortunately out of my price range

i have seat ime in one with 500 hp gas motors and trs drives, 60 was it thats all she was doing, i would like to cruise in optimum fuel burn range at 65 mph

I think - propped right (and most 'book' configs leave too many horses unharnessed) - with a ZF 280, .81 single speed, you'll be cruising at +75 with no strain, and making better than 2mi/gal.

You'll need blow tubes to get on plane, of course, but I think Arneson may be making them now.

The 39 Aronow cats look cool, but they are floating bricks.

thats why i want it, use the 28 skater for hauling ass, use the aronow to haul alot of ass

I think this is one of those cases that goes against almost everything I say on here about how to go fast with diesels.

I won't be insulting but your boat is a solid built boat that has endured the test of time, it's not the fastest but takes a licking and keeps on ticking.

My thoughts based on some experience say you should use large dia wheels and turn them slower maybe a 1:15 reduction or 1:1 as your tallest (single speed) and set your target cruise at more like 60 mph than 70 mph. Your fuel effeciency will be better, it will plane easier, stay on plane at much slower speeds and be a better party boat than trying to make that boat go fast.

If you want to put in hot rods and 2-speeds go for it, think you will have deminishing returns and wind up with a boat that falls short of your top end goals and has lots of money sunk in it, but it's your money to spend.

Joe, im still at a loss of what motors, I like Cummins, but i am going to have to go pre owned ( i think ) i don't know what size i need 350 hp, 700 hp or more...i really need some direction in what powerplants to use....reliability, fuel consumption, performance are whats important to me and in that order.

From what you have said, your two BEST options are the two 6.7L. You won't be able to break either of them, and you'll get both 2½mi/gal and 70kts. You have no bad choices, but you'll be at $40/side, even remanned. The good news to that number is that you do it once and you're done; no top-end after a heavy running 3day weekend.

Call your regional Cummins distributor. They have a substantial re-man business, and everything you get from them is brought up to current spec and warrantied.

MSHS is in Lauderdale; Marcus Platt is the guy with the furry nuts: http://www.mshs.com/ 954.763.3660 and I know they have a couple of N67-560 either in re-man or just finished.

FPT is really trying to open their USA market and may be interested in making deals.

The chance of you finding two good 2,000hr running take-outs is pretty slim.

OTOH, you won't be able to run them hard enough, long enough to make them even a 5.000hr engine.

Props are going to be both fun and joy, but, like Joe said, when you push the sticks even a little, you'll get response and your engines will ♥ you.

You saw the wheels on the Silver Skater? ... there's your pattern: 5 or 6 elephant ears, 20" dia, 40"+ pitch - move some water.

Bob