Beefing up a Bravo 1
 

putting around 530 - 550 hp in my cat . 468 NON BLOWER.

what can I do to beef up the drive and also what precautions can be taken to help. thank you !

if you bring it up EASY to get and plane and dont launch it you shouldnt have to much trouble with the drive you have...

not an expert,but a billet top cap would be my first choice...i did it on mine

Use the search function in the upper right corner. There are several threads discussing this dilemma. It's been beaten like a dead horse

thanks going to try it .

How you beef up a B1??? That's easy. Sell it and buy an ASD#7M.

first question is what year bravo and what model bravo do you have. there are some differences between years like vertical shaft diameter and the difference between models is quite a difference like the bravo x upper gears are not straight cut gears like the xr also the cases are not the same the x has aluminum chimmnies which snap off if the thing ever got launched and re-enteres without throttling back and the xr has steel chimmnies. all the gears in a xr are forged and the x has cast. the lower on a xr is pretty obvius by looking at the propshaft diameter. the shaft on a xr is all steel and one piece and the x has a stainless 2 piece fusion welded shaft which always twists and breaks at the weld. the xr also has a billet aluminum propshaft bearing carrier. you can change the vertical shafts to a better hardened shaft from imco or teague. also other things to know is the newer style sleeker upper case drives are all shimmable uppers as opposed to the older models where predetermined shimming. difference is they say as per mercruiser school i just went to was the newer ones will shift and should have better gear wear.

It seems you never break the items you can easily replace but typically do break the items that you can't replace easily....or at least I seem the break the items I don't have spares for. Therefore, keep an entire spare drive laying around. If your luck is like mine something else will break but the drive won't! :)

Have 2 bravo spares and a blackhawk.. I just hate getting towed home after you buzz up the river turning heads..LOL

Thanks for all the responses.. Is there a reputable guy to send it out to if I want to have work performed. I wont mess with bravo's .

1990 B1 should have sn starting with OL or OF or earlier. That would be the thin floored helical cut gears. They are forged, but then machined for the helical gears. That old of a case is thinner in some spots than the newer ones. They used to set them up pretty loose back then. But the most common problem was pushing the floor out of the fwd driven gear. New B1X uses thick floored gears and steel tower in the case. Also uses the XR vertical shaft, but still has the 1" propshaft. The newer the case the stronger they casted them. A 2004 case will have more meat in it, so adding a steel tower and good top cap with a steel tower is a common upgrade that lives in a lot of cases. There are several guys in my area with that setup with much more power than you have. It must be driven with respect, but most have decent luck with that setup.

What rpm are you running at WOT? The higher the rpm, the easier on the drive, to a point. Less blades on the prop is too. No 5 or 6 blades unless you like maintenance.

Hope that helps.

Dick