Hot Rods Rear transverse spring mount spacing

I have a 36 Ford rear spring that measures 46 1/2 inches along the total length of the main leaf center to center of the eyes, as if laid out flat. Can someone tell me what the spring hangers should be center to center on the rear end. Going in a different chassis and don't have the original rear to measure. Thanks...Greg

 

Take the eye to eye measurement straight across and add the length of both spring shackles, then the amount of spring stretch you want to add. Speedway says the spring + the shackles = the center to center on the perches, but I like a little more stretch than that. When you end up the shackles should be at about a 45 degree angle. The curved measurement is not going to help much.
This is without any locator bars (side to side) as the spring and shackles perform this function. Later models use a looser installation with the shackles way less than the 45 degree angle and used a locator arm. I am using this type of setup on my 33 coupe (with the locator bar).

 

It should measure at 48 1/2" at the spring hangers.