pstorti, I'm not sure as I really don't have any experience running them. I think building it with XR gears would put it pretty much the same as an XR, even though it might be harder on the gears because of the surfacing. So I think you will get a lot of different answers on that. The guys actually running them are going to have the best info. I built one for myself with X gears to go behind a 400 HP small block and I don't anticipate any problems at that power. I haven't run it yet however too many projects!

dsmawd350, the installed height is critical, there is no way to add spacers like a standard drive. But a Blackhawk is not going to work on every hull. That is one of the reasons Mercury dropped them.

I've talked to Gary also, he is great!

I have always wondered what twin blackhawk drives would do in a 30' catamaran with small block power. When you look at cats in this size range that run surface piercing outboards and cleavers they post pretty big numbers for the power that outboards make. I would think utilizing a surface drive, cleavers, and motors lighter than a big block would be a great package and could run big numbers.

Im running the blackhawks which were said to be rebuilt with the newer heavy duty merc gears by previous owner. Which ones? who knows. I had my mercury certified mechanic take off the drives too check motor alignment and to also go through the drives to confirm what exactly I have and the condition. He said that the drives are capable of 500-550 hp with proper throttling for re-entry. He said drives have heavier duty internals than original (he mentioned x, xr can't remember) He said he had tried these drives in the past with little success. The boats that are known to run well with these drives run very well. I would think the bat boats, scarab P29 might be the boats that have added hp more than some of the other boats that were sold with them. Im thinking a couple formulas had them also. Biggest issue with these drives is the lack of quality props or any props for that matter. The merc props are the only ones that seem to stay together. Early testings with some aftermarket props would throw ears off of the prop. I have heard of mix and matching the 3 sets of props, 27, 29, 31 for fine tuning. Not much time was spent on this part due to the hawk project being discontinued. Which also stopped aftermarket shops from R/D. Hoss props and also cleaver made props in the past. I do feel their is a following for these props and drives but probably not worth any large investment due to the low numbers of people actually using them compared to the money that can be made from the current bravo setup.

I've always wondered if the hull on my non step 93 fever would run good with a hawk on it. Always wanted to try it. I know the 242 formula and the 272 ran good with them as well. But we did have big thick aluminum adapter plates for the transom with different drive heights to fine tune it but the one that was on it when it showed up from Stillwater had the best performance so we never changed it.

I have a 20' Cig with an Ilmor 625 Gen III on an ITS Transom Assy with a BH drive. The drive has been rebuilt with XR parts and runs mint! I have at least 60 hours of run time on it without any issues and I run the boat Hard! Obviously my boat is not particularly heavy but with 625 hp the drive has held up nicely. I love the way the boat handles with it.

There is a spectre 30 with small blocks and single prop blackhawks out there somewhere. ( I saw it for sale at one point)

I think an LS blackhawk package would make for light and efficient combo, You could get down to near verado 350 weight and still make 600hp

I have a set of 31" pitch Merc props if anyone needs them. One, I believe has never been run and the other is low hour but has a small ding in the leading edge.

How much are you looking for.

Great drive and cool looking piece ,here s a video of one I tried on my 21 ft LS powered toy but too bad it didn t work as the hull not have natural bow lift and the boat run very flat but still did 95 mph .

and love the rooster !

http://youtu.be/Dh1AVt_vc28

here is that spectre 30
http://www.powerboatlistings.com/view/12781