What is the difference in the Bravo 3 upper?

For example, can I buy a Bravo 3 take the dual prop lower off and put my standard Bravo lower on it?

You have to check the charts for gear ratio's. But the uppers will swap.
The Bravo 1 X has a steel tower in it.. where as the Bravo 3 upper would not. Unless it is an X also..

Hope that helps.
Dick

Its a Bravo 3 X with a 1.81 ratio.

I thought the gear ratio was done in the lower?

I am not sure what combinations make up the ratio for the B3. But in a B1 it can be upper and/or lower.
Bam's site has a chart for each series of Bravo drives. You can find the answer there. If it gets too confusing.. let me, I can look at it when I get home from work, if I have some time.

Dick

I checked these many years ago and found these:
A B3 upper in 2.20 is the same as a B1 in 1.65
B3 2.00 is a B1 1.50
so a B3 1.81 is likely a B1 1.36.......hope you running lots of HP to spin that gear ratio.

Your right T500, I just checked the chart..

B3, 1.81 = 29/27 upper
B1, 1.36 = 29/27 upper. Run with the 15/19 lower gears. So now you need a smaller prop, to run that combination..

Hope that helps.
Dick