727 not hitting second hard enough

When you say "tighten the kickdown" what do you mean? The TF3 does not require the kickdown linkage. You remove it and wire the kickdown lever at the transmission all the way back. The TF3 converts the valve body to full manual. Is that what you did?

I didn’t remove the linkage, I will try it and see what happens, this should fix my issue though? Or a lot of it hopefully?