do all twins counter rotate ? I am lloking at a 272 Formula and the guy told me he replaced one drive with a CR drive .....if so ....does that just smooth everything out ? ...prevent steering error ect ?

All twins SHOULD counter rotate, especially on a performance boat. Counter rotation counteracts steering torque at the helm AND counteracts the twisting effect of the prop torque on the hull attitude.

Example: right hand prop torque tends to lift the starboard side out of the water. Two drives running a rh prop will require lots of weight on the starboard side in order to run level at speed. This means that the boat will have a pronounced starboard list at rest in order to counteract the doubled prop torque. Counter rotation allows even weighting.

Most twin Alpha drive installations do NOT counterrotate.

All Bravo twins DO counterrotate, as long as you have a left hand prop all you gotta do is swap the shift linkage.

Most TRS twins DO counterrotate but I have seen a few that did not.

Alpha drives, at least early ones, only spun 1 way. A friend had a Nova with built small blocks. Every time it left the water, it would jump sideways. Don't know if Merc came out with a counter rotating version later.

Yes, there are LH Alphas. Don't see many of them, though.