A buddy of mine runs a Nordic 28 at about 5000/6000ft and has a 540/600 in it. Runs about 74 mph. Doubt a 500EFI will get you near that number, definately not a 496. I have a 496HO at sea level on a Nordic 28 and I am running upper 60's, but should get 70+ with my new labbed prop. Go the 540 or 572 route, much better engines. I can hook you up with him if you want and you can get some feedback directly from him.

Troutly,

What is the difference between regular production, hand assembled, and blue printed motors?

I was more curious if the B3 can be combined with the HP500 mechanically and if it made any sense performance wise. Can the B3 handle the 5200RPMs in terms of improved top speed with the stock 2.00R drive ratio?

Jamal

Thanks for the input from the high altitude guys. From the sound of it, a blower is probably the way to go. Maybe the question now is,which motor is a better blower candidate? Has Whipple released their 496HO kit yet? Dustin???? Just out of curiosity for you 500efi owners, how easy is it to winterize that motor. I understand the 496HO is very easy and quick. Thanks for all the input, this board is invaluable!

Thought I'd chime in here with the high altitude stuff and 28 foot single power. Donzi22 is right on the mark beings we both boat at the same Utah altitudes. To run 72-75 in a 28 foot boat at 6200 ft. will require some big hp. As Indy stated, I run a 580 hp 540 in a 28 foot Nordic and I run about 69-71 GPS at 4500 ft. and 74 to 76 at 1300 ft. The factory Nordic 28 runs 72-73 with a HP500EFI at Havasu which is 400 ft. Beings your power at 6200 ft. elevation will be down 23% the HP500EFI will be putting out a wopping 362 pshp which should push the Heat into the 62-63 range. If you Whipple it you should see 74-77 at 6200 ft. We have a guy locally running a new Nordic 28 with an HP500EFI with a Whipple and he runs 80 mph at 4500 feet and 88 at 1300 ft.
Bottom line is altitude sucks! However when your running against someone it's still apples to apples.
To achieve your goals you'll be looking at the HP500/Whipple combo and you'll have a rocket when dropping down in elevation. You'll also need a good selection of props!
Hope this helps...
If you have any questions regarding the Nordic drop me a line.

496 kit is not out yet, and as far as best motor for a blower, the 500 HP has far better parts, makes more power, and a hell of a lot better looking, I'm still a sucker for that metalic blue. One trick we do is change the blower pulley to make up for lost atmosphere, which allows you to run the same propshaft as you would at sea level, although you don't make the exact same power, it's much closer. So at 6200 feet (how do you breath? ), I would put our 8lb. pulley on and it will end up having approx. 6lbs. at that level, the 500HP will make approx. 710-720hp at 6200ft!! A pulley change takes a whopping 5 minutes.

The 496 kit will also do the job, but will not make the 500HP power. It will be closer to the 600hp level. The speed really depends on the boat, some may need more power than others to go the 75 range.

You can email me if you have any questions, [email protected]

Thanks,
Dustin

This thread has been run a few times. You can find a lot of good archive data. The biggest question is how long will the GM Mark IV Gen VI block be supported. High performance big/small blocks are in transition. With GM's decision to change the entire motor line-up it caused a lot of headaches for the consumer. I have the new 496HO motor in my Donzi. It is a hard hittin peice. The problem lies in the aftermarket availablility of parts. With the total change of the heads, block and firing order it renders the previous Big Block parts useless for 8.1L upgrades and modifications. The reason Merc has not built a 500EFI, or supercharged version of this block is there is no where to turn for the aftermarket parts to support it. Hopefully the aftermarket parts will start to appear. Aside from the marine applications look at NASCAR, NHRA, IHRA etc... Sometime in the future if the parts do not become available it will become a major problem in the recreational markets that require better crankshafts, rods, camshafts and all the other goodies it takes to go from the Stock delivery to the ultra- High performance needs and requirements of the consumers. I just hope GM produces the legacy blocks long enough to get the R&D finished for the new 377 Small Blocks and 496 Big blocks into the hands of aftermarket distributors. I decided to make the plunge to the new technology now and will continue to do so in the future. If all of GM's production vehicles are going to have the new engines and only a limited market of old technology remains it only makes since that the old blocks and parts availability and more importantly the prices will be prohibitive to maintain. How many years are left? 5 maybe 10: Who knows. The GM corporate web site also has a lot of good data on the new engines as well. Good thread. Thanks, and hope things work out with your decision.

[ 01-07-2002: Message edited by: DONZIMAN2 ]

Badcat,

Sweet pic, How many hours do you have on the 500efi and Whipple.????

Donziman2, the GM blocks are going to be made, just not at the same facility as before and not in the quantity levels, but the blocks are still being used and will for a long time. The parts will always be made, as theres so many around. As for the 496, over the next 2 years, parts will be pretty low, you won't see many other upgrades just like you said, but slowly, as more get out there, you will see the changes. Custom parts can always be made, just very $$costly.

Thanks,
Dustin

the 502 upgrade is typically about $11K over a 496/ho...but if you want that extra MPH you could do it.
Then again you could get the 496/HO and put on a whipple for 6 grand and save $5,000.

I'd get the 496/HO and put a whipple on it. You'd have no problem getting you MPH....especially if you get a Sunsation 288. My 288 with bone stock 496/Ho will do 71 on GPS at sea level.

- jeff

Sunsation288

Thanks Dustin, I agree. A lot of aftermarket peices are out there for the old style motors. I have had good luck with the Merlin Blocks in my Drag car programs. With the universal demand for these units they will survive. It will be nice when the aftermarket peices start showing up for the new design motors that GM is building. I feel there is a tremendous amount of potential to be had in the new parts. In stock form they are already in good shape. When the motors have been around for a few years I think we will see a lot of peices coming on the market as demand increases the profit potential for the builders. Thanks again for your input and keep up posted on your efforts. See you.