ekcivic1

Ok so my dad has a 1989 Mach 1, 23 feet long and it has a 540hp 454 with a bravo 1 outdrive. Ive been looking at the outdrive for a while and I noticed the nosecone part is about 8 to 9 inchs below the bottom of the hull. So my thinking is that if we raise the outdrive, then we should gain some mph. Would this be a good idea to do, say maybe bring it up to about 4 inchs from the hull? Would there be any drawbacks from it, or is this just a stupid idea all together? The reason im asking is because the boat only runs about 63 mph and i see baja's and other similar sized boats running 70mph with the same power.

Griff

Try to find a -2" or -3" Imco shorty lower. Way to much work to raise the drive and redo the transom for something that might work.

ekcivic1

Alright, so depending on if we go with the imco lower unit or just move the entire assembly (we have a friend that will let us use his garage and he will redo the transom for us), why would it not work? Is it possible that it would slow us down? I am expecting that it will have a harder time coming out of the water.

BY U BOY

Find A black Hawk

ekcivic1

By U Boy: i have never heard of a black hawk. What exactly is that?

Vinny P

This is a Black Hawk. While not very popular, they are around..

ekcivic1

that thing looks crazy! So it looks like it uses the same mounting area as the bravo. about how much does that raise the prop shaft if lef tin the same location as the stock bravo? And what is the purpose of the twin props? thanks

BRUCE SEROFF

sounds to me like your drive is way deep. if you raise it, you should see better results.

BUT!!!!! as stated above, It would be alot cheaper to just put a 2" shorter lower unit on and see if you get better results. That may still not be enough. If it doesnt help, you can easily sell the lower. If you raise the drive and gimbal, you have to raise the motor and exhaust which means you have to patch the transom and recut for drive and exhaust. If that doesnt work, you have to put it all back to original and you just blew a chit load of time and cash and have nothing to sell.

2 " lower will make a difference though.

good luck

ekcivic1

Bruce, thanks for the reply. I guess what i am trying to find out is if there have been any negative results with raiseing a drive, whether it be lower unit or whatever method of choice. A couple years back i talked to the driver of attitude racing (forgot his name) and we talked about the same topic. He felt there was to be huge gains made by raiseing the drive, or even an extension box. I also remember talking with my dad about his 14 foot jet style boat except it had a 200 horse black max outboard. He said he had to keep raiseing the motor until it finally got the top speed he was looking for. But of couse thats on an outboard, totally different ball game.

BRUCE SEROFF

I had a 89 Baja 240 sport w/ 525hp and a very conservative X dim from the factory.
i installed a 2 " shorty and had very good results ie 3 mph gain and much better handling. I dont think you could possibly have any negative results.

prop shaft 4 - 5 inches below the bottom of the boat would be ideal.