Thanks...I really appreciate the effort. At least I have an idea now.

 

did you ever get your measurment you were looking for...

 

No everyone I've got to get a measurement keep getting 40" to 40 1/2" from rear of frame to where the center of axle lines would meet when I took off my leafs and hangers I measured 36 1/2" if it was an inch between mine and there measurements I'd compensate but the 4" has me confused I'm about to just put it where it looks good and mount everything one thing before I do this is should I put it towards the front of the wheel well alittle so as the suspension compresses it will center the wheel in the well more or is my theory wrong and how much does a leaf push the axle back as it gets compressed? If someone can answer these questions about the spring load ill go ahead and mount them where I think they will be good

 

No I think ur theroy is correct. Its gonna push back a little with copression but i wouldn't think a whole lot.

 

Ok I wasn't sure how much the 8" super duty springs would push it back compared to the stock springs I think ill offset it an inch or so towards the front of the wheel well if I run into any problems its just more holes to drill and fill in on the frame I may need to get the super duty leaf mounts that have the shackles on I have 4 of the super duty leaf mounts the ones that are solid mount using all 4 may kick my rear up to far using the SD mounts because stock ones ain't wide enough to fit the SD leafs in just like the front ones don't fit