What's the difference between the Bravo old style and swept back XR style drives. Is it internals or just outer appearance?

Both internal and cosmetic differences .

Agreed, little inside, little out.

One thing stays the same, real power will trash them both.

In the end, same old, same old!

If by chance you meant is there a diff between the XR and the XR Sweptback the answer is only cosmetic diff between the two .

The insides are identical. The exterior is different. I have pondered whether the sweptback adds structural stiffness but I doubt it....

The swept backs are prettier - IMHO. As RE stated, they all break if you throw more than 501 horsepower at them or your prop comes out of the water more than once.

Just curious, would an xr bolt to a standard bravo hp gimbal? Or are the spline count, shafts different than a standard b1?

They fit. Same helmet bolt pattern, same splines.

It will bolt up just need the later syle gimble bearing to clear the larger u joints. The bearings inner race is shorter on the drive side.

Thanks appreciate the info. Still haven't chosen which drive ratio I'm going with on my repower, good to know it's just looks, which I do like the new style

they claim more upper support for the bearing...