I have new carbs to be installed on my rebuilt 454's before trying to find the perfect new props. I have only the labbed set of mirage props that came with boat. The pitch is 23 but struck thru with an x and 24 in it's place. I can turn these props at 5300 at 75 mph (have seen 77.1 mph twice). The slip number ranges from 3% to 6% with the pitches listed above. Someone told me that with a labbed prop you go by the original pitch when calculating. That makes no sense. He told me with a slip number so low I was doing about as good as it would get. I read that most fountains my size with single step are running a hydromotive quad IV instead of my 3 blades. Can a prop vendor even start to figure out what I need with the performance numbers based on really a unknown specs of the labbed props I have now? What's the proper steps to get the correct props and dialed in?

TTT, any thoughts?

It is tough to make exacting judgements without seeing a propeller that has been worked on by some one else. However, as you said, using 23 or 24 pitch reaps slip numbers that seem to good to be true. If the speed and rpm are right on, your speed number will be hard to beat. There are other personalities that may be desireable though such as low end or acceleration or fuel economy.

If you are happy with the overall feel and personality of the props you have, and 5300 rpm is a sweet spot, I guess I would be also inclined to say you are doing very well.

Determine your goals and we can discuss this further.

Brett

Brett, Thanks for the input. Sure would like to use BBlades to purchase my props.

Boat is at the tuner getting new carbs, rocker arm/valve spring adjustment checked, timing adjusted, etc, to be running top notch. After verifying engines are tuned up, I would like to start the prop selection process.

I am hoping the Mirages (non-plus, turning in, listed above) are pulling the stern down and holding me back on top speed. 99.9% of the boats like mine are running the Quad IV to lift the stern. I have read that the straight hull Fountains came with the mirages and when the step came along Fountain used the Quad IV. My factory test sheet showed Quad IV 22" were tested at 72 mph. Why the previous owner changed the props I don't know.

I checked in with Brad a couple weeks ago, no Quad IV's in the rental program in the pitch I might need. If I was to commit to purchasing from BBlades, can I swap out the Quad IV's as many times as needed to get the pitch correct? I understand shipping and rental cost. Just didn't know how you handled the problem of props not in the rental program.

Hi again,
We normally have the Q4 props in the test program and do have some pitches now. Hydromotive had issues with their foundry this year and we have had back orders all summer. If we don't have the pitch size in our inventory you need, we will get it for you. We normally have every size in sets that Q4's come in. As the summer closes, we do tend to not replace a set that may be sold (not returned from testing).

The Q4 props can lift the stern more than other props. There is a long story about the Hydromotive props being used on the Fountains during the late 1990's into the 2000's. I wrote about that story many times on this forum. I'm sure you can find the stuff if you search back. Bottom line is test different props till you find what works best for your goals and driving habits.

Yes, you can test as many propellers as you need to. We don't have a exchange program. Our program does not require you to buy. You pay the test fee of $45 per propeller. After one or two tests you should know exactly which casting to work with (with our help). You are never required to purchase anything.
Thanks,
Brett

Thanks, I talked to Brad this morning and I think we have a plan of attack!