Is the bravo 1 standard lower gears the same as the xr lower gears other than a bigger prop shaft is the housing different ?????Need info I know the tops are!JOHN SR

the driven gear has a larger bore than the standard B1

When running some power 650 hp would the standard bravo hold up or could that gear and upper shaft be changed????Have a chance to buy some lowers and need a place to start we are running 650/700 hp.Just don't have the money now for the high doller stuff. JOHN SR

ttt

Been running a XR upr with bravo 1 lower for years with 650 - 800+ HP. Never broke either. Run it stupid and it wont last a day. Use your head and it will last a long time.

For a point of reference, what's your boat weigh?

I run about that for hp on a twin engine boat, 7500lbs. I have trouble twisting propshafts and vertical shafts but gears no problem. I keep on close eye on the splines and if I wing it (bad throttle work) can end up having to swap out a shaft.

28' AT single with fuel and people approx 5700lbs.
Running a 5 blade Maxximus.
I hear all the time people breaking drives.
Run it like you know what your doing and it can live.
Drive it like a ars with throttle down and no idea of to back off or punch off the line and it wont last an hour.