What is the max speed that can be expected out of a bravo 3 before you start to loose efficiency? I am thinking of switching to a bravo 1 from a bravo 3 on a 20' 454 powered Cigarette. A imco 2'' shorty may go on too. I just do not want to spend a bunch of money and see the same results as with the bravo 3. Any info will be greatly appreciated.

Probably depends on the boat also, but you're probably looking at 70-75 MPH. There are people running 600+ HP and running 70-75 MPH in similar sized boats as you, and running BIII's. Another member will probably jump in here shortly who is although he did break, then upgrade upper gears as part of the learning process finding out what the torque from a Whippled 502 MAG can do to a Bravo.

If someone can only hit 75 in a 20' sportboat with 600 HP I'd say they already went way past efficient. It should only take 400 or so for those speeds with a single prop. I thought the BIII was a dual prop for heavy boats designed for 55-60 top speed?

I don't know how fast the bravo III is designed for exactly but it is not your best bet for a light fast boat. The Imco shorty or a bravo I with the correct prop would most probably see a nice increase in speed. On your boat the twin prop setup is best for pulling skiers and general driving with a heavy load.

I am already hitting 72 on speedo and about 5100 on rpm with stock 454 efi. With an exhaust system it may hit the rev limiter and a prop tweek or change will be needed. I think it would be much easier to work with a bravo one.

I've heard their good up to the 65 MPH
area.

Look at the prop sets, they resemble the old
"elephant ear" props used back in the 70's.

Volvo's made twin props run fast............they
seem to have it figured out , prop wise.

The lower gearcases of the B1 and B3 are
very similar.

With the B1, at least you have some "options"
with props.

The volvos ran pretty fast with a special high speed drive & propset. They still hit the wall at around 75-80mph. Too much blade & drive surface area.

The biggest improvement will be with the props. Most B3 props are not cupped which makes for buku slippage. I don't think that you'll be disapointed with the B1

Don't you have a buddy with one that you can try.Not much to swap them.I would think your boat will perfom much better with the bravo 1.I know of a few people that have had reliability issues with the bravo 3.Lots of volvo duo props on big performance boats in my area.Aparently the volvo is better for more speed than the bravo 3.It's kind of cool with the built in full hydraulic steering.Stock bravo steering is a bit snakey obove 60mph.

I had a 23ft boat with a 496 HO and a B3, it ran at 65gps all day long, with about 6% slippage. I know guys that are running simular boats with the B3 in the mid to upper 70,s.
Joel Bronson, of Bronson Hill Propellers knows more about the b3 props than anyone that I've ever talked to.