im planning on installing my 1000hp blower motors this winter, 1.5 to 1 ratio #3 drives but am looking for a pair of #3a lower units. im going to install extension boxes. bw 1 to 1 ratio 72c's. want to run a 4 blade but have no idea of what pitch to start off with as this will be a totally new combination. tres had a mistress going 97 at lake X with #3's, boxes and 850 hp a side. i'll have 1000hp a side so am hoping to see 100 mph or at least thats my goal. any input would be great. i will have a set of #3 three blades for partial trade. julie or any of you other prop peeps give me some advice. thx in advance ratman
BTW boat is non stagger set up.

What is the weight of the boat?

Julie

If you can't find any 3A's, you may consider adapters to convert to the 26 spline. At least then your prop selection ability will be greater. You will be pushing over the limits with 1000ph through these drives.

Besides pitch, we will need to discuss diameter as well. On these aplications, diameter is as important.

What rpm do we need to turn the engines. I'm assuming in the 6000 rpm neighborhood? With a 1.5:1 g.r. you will be in the 30-31 pitch range at 6 grand. If you wish to spin them slower, you'll need to pull more pitch. These numbers are conservative, concidering the hp/wt ratio does allow this boat to run 100mph.

i guess weight is aroung 10k to 11k depending on have many beers are in the cooler

OK we're still in the ball park. What about the rpm requirements from your engine builder?

6000rpm give or take a rev or two

I would suspect that you will need 30P propellers to see 100 mph. The propellers can be difficult to find and adapters may be the way to go. If you find adapters I may have somedthing that you can test.

Julie

julie im putting some 3a's on when i install the blower motors so that should help with prop availability. i'll give you a call in a month or so when im ready to start testing. thx, have a great holiday, ratman