Will not shift out of 1st

Found it! When I had the trans rebuilt I asked the guy to put a shift kit in. He used a B&M. The kit provides a 1/4" check ball to be placed inside the spring of the 1-2 shift control valve but states for off road use only (??). He put the ball in the 1-2 shift valve. The 1-2 valve seems to only have about a 1/4" of movement as is so w/ the ball inside it wouldn't move at all. I removed the ball and put it back together. Now it shifts great. (see the .pdf instruction in the link)

http://www.bmracing.com/PRODUCTS/Ch...-66-77-Chrysler-Dodge-Plymouth-TF-A-727-A-904

How should the trans shift w/ a shift kit? Under part throttle (just cruising) it shifts to 2nd around 1500 and you can barely feel it. Should it shift hard when you're easy on the gas? It does shift hard if I manually shift it. Should I open it back up and put the ball in the correct spot?

BTW, this was my 1st real ride in a big block a-body. These things are awesome!