Can I take an ASD6 1721 borg warner chain drive and upgrade it with stait cut gears to handle 620 hp single 7500lbs? anyone done it out there?

Get a hold of Rick at Arneson industries he has all of the answers http://www.arneson-industries.com/

Rik's direct line is 415-485-0788. Jeff

Chain drive is for "same rotation" (same prop rotation as engine rotation).
Gears are for "opposite rotation".

Chain and gear have same duty rating.
Why you wanting to swap?

Being a single, the gear (RH Rotation) will make the boat handle better with a standard rotation engine.

Wouldn't that depend upon which side the helm is on??

You know there is really nothing wrong with that chain drive the way it is ,it serves it pupose for what it was designed for, I realize that now.

I wish to say that Rik at Arneson has been more than helpfull with the construction of my new 35' canopied offshore stepp vee . He has put my boat way ahead . Craig

Thanks RIK