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New power, old drives........

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Old 01-26-2010, 12:54 PM
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Default New power, old drives........

I am thinking about upgrading from 500hp's to 540 CID's at about 600 - 625 hp. The boat is big, and heavy (38 Vee), with stock Bravo drives (1996 vintage). I have been considering a drive upgrade, but after spending 6 months of mortgage payments on engines, my wallet is pretty tapped out. Every once in a while I see used XR drives go fairly reasonable. What is the difference in the XR vs the regular Bravo. What is the relative power they can handle, and do the drives interchange on the gimbal.
Thanks for the input.
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Old 01-26-2010, 01:49 PM
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A buddy and I made 540's out of 500's a couple winters ago. He had reg Bravo's I had XR's. (His-42 Sonic, mine-38 Formula). He made it til July when he blew the first bravo upper apart......not even salvageable. I made it 3 years before I cracked and upper....mine was repairable.

He bought a pair of XR uppers and re-used his bravo lowers, still running fine now 2.5 years later. To use the XR upper you'll need a new XR gimbal bearing but otherwise it will fit the regular bravo transom assembly.
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Old 01-26-2010, 06:13 PM
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Why do you say you need a new gimbal bearing? I switched from standard bravo 1 to XR and did not change anything except the outdrive.
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Old 01-26-2010, 06:31 PM
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My understanding is the XR gimbal bearing is thinner because the the XR U-joint is bigger.......the thinner bearing gives the U-joint the clearance needed.
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Old 01-26-2010, 06:57 PM
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I have not experienced any problems. Now I have a Cat and dont trim up to put on trailer, so drive is not at any extreme angles. Maybe that is the difference?
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Old 01-26-2010, 08:47 PM
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So let me get this straight, I could use my existing bravo lowers, and just hunt around for some XR uppers ? Is that where the weak link is located ?
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Old 01-26-2010, 09:25 PM
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Quote:
Originally Posted by doctor_ratz View Post
So let me get this straight, I could use my existing bravo lowers, and just hunt around for some XR uppers ? Is that where the weak link is located ?
Been done many times......and IMO the upper is the weak link.
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Old 01-26-2010, 11:32 PM
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Upper may be the weaker link, but it is still very possible to twist horizontal and vertical shafts. In a worst case senario you twist a prop shaft off and loose your prop. I do have 2 XR lowers for sale in swap shop that are in great shape. If interested PM me.
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