Ok, so now that there's confirmation that Flex-O springs and non Flex-O springs are NOT the same, also know that you will need the overload spring bumper brackets for the frame, too. You can see them in phyrekitsune's first picture...

 

eaton spring is a great website but the leaves they refer to are on pre 67 f100

I also wonder if the actual length of the springs is the same but the rear shackle is set back farther setting up a flatter spring vs the non flex having a shorther shackle to shackle mount and a bigger arch?


Also the location of the brackets is the same I believe but does the flex eyelt set the end of the spring farther back. As it was also explained I could use the flex setup on the springs for the 71 non flex...........

just stirring the pot.....

 

Their website says 66-71 but my 72 short bed has a 9 3/8" with Flex-O and factory overload springs. The website also lists the exact length of the springs.
Click on the words "EZ Ride Shackle Tech" in my previous post.


"The EZ-Ride springs measure 24" x 32" and the non-EZ-Ride springs measure 24" x 28"..."

 

Dang. It's good to know I was measuring wrong, so thanks for the link to Eaton's site. Also seems I'm the one being difficult to convince, but I think I'll sway the other direction.