I recently purchased a 79 k10 and I'm wanting to do an axle swap with a 14 bolt rear and a Dana 60 front.

I found a set for 1400 dollars
The 14 bolt is a full float with new posi and 4:56 gears
The 60 is a king pin with new 4:56 gears

Is 1400 a fair price for the pair with new gears?
What should I look for when buying used axles?

Also my truck has a th350 with a shift kit

When I drive the tranny shifts trough first and second straight to third in about a 3 second period unless I gun it then it shifts long and hard like it should. Any idea what could be going on or how to fix it?

Any help is much appreciated thanks again guys