Does anybody sell 8.25 or 8 1/4 performance axles for a 73 Dodge Dart. I can't find axles anywhere and custom order forms don't list 27 spline.  

I have an 8-1/4" A body axle waiting to go in my 73 Duster and have encountered similar problems looking for parts.  Randy's ring and pinion lists both 27 and 29 spline axles, mostly for trucks.  1997 and up used 29 spline anyway so getting carrier parts to swap over to 29 spline might be the way to go if all the aftermarket stuff for an a body length axle is going to have 29 splines.  I have yet to see an a-body axle listed as new anyway.

If you are looking to put in heavier duty axles in your 8-1/4 you may want to think about building up an 8-3/4 rear instead.  You would probably break the rear end gears before you rung an axle on that 8-1/4..

look in active posts at the driveshaft my have to go. maybe the guy still has the axles.