What does contant mesh clutch mean or how does it compair to other clucthes.

 

I think you mean, constant mesh transmission. Which means the gears are always meshed to the mating gears, and a dog slides back and forth to lock one set to the shafts, while the other pairs are frewheeling.
Check out this web page for more details.tranny

 

Great link.

Just an FYI, the engagement dogs aren't that size typically. They are more like an oval shape and the holes they go in are larger. There are typically three or four engagement dogs on a gear.