Anyone have an idea what it would cost to change my gears from 1.33 to 1.50?

It depends what ratio upper gears you have combined with your lower gear set. You may have a 1.18:1 upper set combined with a 1.125:1 lower( you multiply the ratios to get the final ratio of the drive) to get a 1.33:1 drive or you could have a 1.33:1 upper with a 1:1 lower for a 1.33:1 drive.
The best combination would be the 1.18 upper because then you only have to change it to a 1.31:1 upper ( whic.h I have in a straight cut forged gear)
to make a 1.48:1 drive. The original Mercury 1.33:1 uppers are not as strong as the new forged gears that I have.
Gary
612-247-7081

wouldn't it be cheaper to change the trans ratio?

I don't think that is advisable/possible. All the Velvet Drive transmissions that I have seen used with the SSM drives, whether they are # 3, 3A, 4 or #5 drives have all been 1:1 ratio. I don't think you want to mess with the gear ratio in the transmission.

you CAN'T change ratio in a velvet drive. you CAN add a reduction gear to the back of it like every inboard shaft boat has. but then you have to move motors forward 4 to 5 inches and find a nonexistant coupler to the outdrives.