Lower gearing on an 08 SD

I've got 7500 miles on my 08 SD now and want to lower the gearing. The standard 08 sprockets are 16 front and 38 rear so it looks like the only practical option I have is to go larger on the rear.

KTM offer 39 and 40 tooth rear sprockets, does anyone know if the standard chain is long enough to accept either of these and has anyone actually tried a 39 or 40 rear on an 08?

Sure is....you just need to flip the block adjusters around 180.
You'll be good to go.

Sure, there really isn't a 'how do' but heres the best I can do for ya