Is a 1:36 lower compatible with a 1:50 upper? What would need to be changed? Any help would be appreciated. Matt

Is the upper an Bravo XR?

Yes it is an xr upper. Sorry I probably should have added that

The boat is a 1989 28' Scarab Excel with a 540 in it. The dyno was 645hp. The 1:50 that it has now took some damage and I ran across an Imco 1:36 shortie and I was wondering about pros and cons with that setup.

Might have to re-prop with the 1:36

To answer your question your ratio will be 1:36.All XR uppers are the same ratio.If you had a Bravo 1 or 3 upper that would change things.