Hot Rods Difference between Ford 36 & 39 axles

I have a 39 front axle for my 36 5w. I found a complete 36 front axle and if it is cheap I hope to pick it up.
What are the differences between the two?
Do they take a different spring?
Thanks

 

The 39 axle is wider from kp to kp. Will take a longer spring. 32-36 axle looks the best imho. This thread has a lot of good info

http://www.jalopyjournal.com/forum/threads/ford-axles.55439/

 

Okay thanks

 

Also if your using the original wishbone the 39 axle has the perch mounts in different locations. The 39 axle will def limit you steering capabilities as the distance from the king pin boss to the wish bone boss is narrower in the 36 axle than the 36 axle.