[joedoh]

if your bar measurement of 13" was related to the bar measurement of the lowers as 21", you still have the problem. measuring eye to eye isnt going to make it better. fix these problems:

your upper bars point down while the longer lowers are straight, this will always cause pinion/roll steer problems. you want them to be close to level when at ride height.

your upper bars are way too short. looking at them from the top this is visible, the upper length looks to be less than half the lower length. you can only measure their length STRAIGHT ALONG THE FRAME, it doesnt really matter what the actual length of the bar is. the effective length, measured straight along the frame, that is how long the bar is. not eye to eye, not just the bar length, all of that is irrelevant. mark two spots on the frame, the centerline of the axle and where the upper bar attaches to the frame and measure straight between those two points. that is the length of your upper bar. if it helps, imagine it as a big rectangular piece of steel instead of an angled bar. even though you can draw a long line from corner to corner of the rectangle, how long the rectangle is measured along one side is how long the rectangle is. thats it.

the upper arc of operation will be a much smaller diameter circle than the lower arc of operation, so the lower mount will stay roughly stable in up/down motion while the upper will not, it will move forward and back dramatically.

having the lower bar mount kicked forward of the axle centerline is pretty standard for 4 links, especially with a shock mount on the rear.

edit: I just rotated and enlarged your picture so I could see better and it looks like you are welding to the cast part of the rearend. this will probably break under use, welding to cast is possible if you preheat it with a torch and get it cherry red but it takes special rod too.