I have a 2005 Formula 370 SS with 496 HO's and Bravo III X drives with the factory 26p 3 x 3 props. I'm looking to upgrade to 25p 4x3 XR props and was wondering if these props will cause any reliability issues with the drives. I'm really easy out of the hole and either idling or cruising at 3500 - 4000 RPM ninety-nine percent of the time. Any thoughts would be appreciated.

I ran them for years on a standard Bravo III drive with no adverse effects.

Thanks, for the reply. Curious, what size was the boat and what engines?

26' Chaparral, 496 MAG. Single engine boat obviously but heavy (6K + wet).

I don't see you having any issues, and just for extra care don't drop the hammer, ease into it. Note only the upper is an X, the lower is the standard B3

Never tried the XR props but used the Hill Marine 4x4, with XR upper and standard B3 lower. Single engine Formula 27PC, about 11K and 530HP

HI, I upgraded my bravo III 3x3 to 4x4. 3x3 were 28 pitch, 4x4 are 26 pitch. Noticed better fuel economy and boat gets on plane quicker then before. No change in RPM or Speed. I don't see how 4x4 or 3x4 would strain the drive. Good luck.

Thanks for the input everyone. From what I've read, the XR props should give me an extra 2 - 3mph in the 3500 - 4000 RPM range and figured that if I'm pushing the boat faster at a given RPM, it may be putting extra strain on the drives. Or maybe the props are just more efficient, not sure how all this works on a boat. Mercruiser also released these props with the XR drives with the heavier duty uppers which made me think they may cause problems on the standard upper gear set. I'm really easy out of the hole though so I think I'll be alright.

More ears on the prop always causes more strain and wear. How you drive it will make up for it. As you said, easy out of the hole and roll into the throttle when on plane. No hammering and you’ll be fine. I just bought a 400ss with 500efi’s and am curious myself about changing to the 4 blades?? I, coming from the go fast world and don’t know enough about the B3’s to decide just yet.

Merc went to standard 4 x 3 (elephant ear, not XR) prop sets on their standard Bravo III's a few years back.