Thanks for all the info. guys! Never a question unanswered on OSO!
Jason

My buddies 96 glastron had the B3 with the extended trim tab mount mentioned above, so it is likely you does too.

Not to highjack the thread. I just baught a boat with what seams to have a b3upper and a b1 lower. Not sure if this is a good or bad thing

All depends on what ratio it is. It should be stamped on the side of the upper towards the front.

There's 3 ratio's of bravo uppers ( 27/29, 27/32 and 23/30)....that equals 1.36, 1.5 and 1.65 with a bravo 1 lower,
It produces a 1.81, 2:1 and 2.2:1 with a bravo 3 lower....the upper doesn't care which lower it's mated to

I have a buddy with a 2008 Sea Ray 290 Sundancer looking to do a swap from B1 to B3. Let me know when you are ready to part with those.

The upper CAN care what lower it is mated to! You need to be aware of "oiler" vs. "non-oiler" compatibility. Just sayin.

What is you application that your talking about...if you take off a bravo 3 gearcase and install a bravo 1 gearcase you WILL lose acceleration out of the hole..there is a reason mercury installed a bravo 3 to begin with. On larger heavier applications especially single engine applications going from a bravo 3 to a bravo 1 will turn the boat into a sled out of the hole..secondly all bravo drives and transom are not the same..there are seriel breaks just like glenamy 242 states plus x series are different. I did a bunch of testing on a 27 formula single dts engine and I took off a bravo 3 gearcase and for testing purposes installed a bravo 1 gearcase and I could have eaten a 2 course meal in the time it took to plane that boat off..not quite that bad but you get the picture..if you aren't concerned with acceleration and are trying to achieve top end you can change x heights to get there but that's a whole different conversation for another day.