Does the current setup have an open driveline or a torque tube? What is an "AK" BTW? I'd suggest a SM-420 4 speed and whatever rear axle matches your front wheel bolt pattern, if possible. Are you planning any kind of modern upgrade to the front suspension and/or brakes along the way? It would be a really good idea to have the wheel bolt pattern match, front to rear.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!