you have a choice.. 1.5 or 1.65

[Rootsy]

ratio for a bravo behind an 18 w/ smallblock? which setup is better? especially if you plan on eventually running some kinda sorta serious power...

[Formula Jr]

1.5

[HP 600SC]

Neither one is better......but with the 1:65
you can swing a larger prop and still have great mid-range acceleration.

[Woodsy]

Jamie..

How are bud? Anyway, you remember RanMan's boat... he is spinning a 25P Mirage on a B-1 with a 1.65 ratio... that little 18 flies.... You can always change the ratio when you add some HP... its about $500 for gears & labor!!

Woodsy :D :D

[Ranman]

Woodsy's right, My B1 1:65 spins a 25P, and runs pretty strong. However, it seems that a lot of the Hot Boat companies that run big power like to run the drive ratios in the other direction (ie 1.3:1). In theory, I think if I put too much HP in my boat, I'd have problems finding a big enough prop to suit the application. In order to get the prop size down with big HP, you would have to re-gear to a higher (numerically lower) ratio. Does anyone agree with this thinking? What are the advantages/disadvantages of the different ratios (1.3 @ 21P vs. 1.5 @ 23P vs 1.6 @ 25P) given the same engine configuration?