Rear transverse spring specs

I didn't want to hop on anyone else's thread. I have some questions while I search, anyone have a link to a post or a site to ID springs. Trying to find out what I have and what will fit. I have 41 1/2" cl to cl on the perches, I've read that the model T spring needs 43".

1. Anyone know the perch span on a stock model A rear



Here's mine (the model A top leafs are gone now):

 

Ok, I just found the answer to question #1,
Model T is 47 1/2" perch to perch.
Model A is 49 1/2" perch to perch.
'37-'41 is 48 1/2" Perch to perch.

 

I hear the 40 front spring is 39-1/2 with mounts at either 41-1/2 or 42-1/2. Both perch measurements are stated in several places.

 

Still reading, has anyone used a '40 front spring on the rear of and A on top of the axle (like a stock A). All the ones I'm reading are behind the axle.

 

A '40 front spring will bottom out on the banjo if mounted above.

 

Does the span of the spring perches look ok (for function) in my picture or should I move them closer to the backing plates (and get another spring).

 

are you using 35/36 truck rear bones and not connecting the spring to them?

 

that looks like the front spring from a 1937-1941 except if it were, it shouldn't fit in a stock Model A rear crossmember since later front springs are 2" wide and model a crossmembers are designed to take a 1-3/4" spring. all that being said, that crossmember is designed to work with a 'banjo' style spring (model T or model A). that spring will bind and slap in that crossmember and inevitably lead to a pretty rough ride. i would do one of two things:
1. get a T or A spring to go in that crossmember with the perches you welded on that rear already and run the crossmember the way it is
2. keep the spring, take the perches off that you welded on and run the spring off of the '35/'36 wishbones you already have. you'll need to make a perch off the back of the stock crossmember to hold the spring farther back but it'll lower your car in the end.

 

The spring that's in there is about 2-2 1/4" wide. I was thinking of doing the bolt on A perches (perches cut off an A rear with the top 2 bolt holes) and then a T rear spring. The set-up I have now needs to come down a bit anyhow. I was going to reverse the eye and loose a few leafs, but was unsure of the reaction of that spring.

 

if it's 2-1/4" it's a later 1940 type rear spring. it is still not designed to be used in a crossmember like that.