th400 shift hesitation

[chevyv8_power]

I have a TH400 with a B&M transpak shift kit and B&M megashifter. The problem I am having is when I ratchet to the next gear there is a delay before it actually shifts. This is affecting drag race consistency. I have 150 psi line pressure. Fluid level good.
One thing that I thought could be affecting it is the all rubber vac line to the modulator. Could the flex create a delay?
Also I am not certain if I have the electric kickdown working properly. I was hoping someone could shed some light on how this works/what it does and how to set it up properly. Switching to a different carb made the pedal stroke different.
Another thing I have heard and am going to check is that the shift linkage could need adjusting. It could be in between gears or something.

[no_bite]

if it helps.....there is a difference in the arm "throw", between a vacuum secondary carb and a double pumper. the double pumper has a longer throw. a lot of people are unaware of this when they swap carbs. this would affect the kick down linkage and cause the double pumper not to open all the way. but it sounds like you have other issues.

[jmarkaudio]

Try disconnecting the electric kickdown, it is not necessary. If you have the kickdown it is obviously not a manual only shift. You can adjust the modulator and play with governor springs and weights to make it shift sooner at full throttle in drive, it will then allow you to manually control it to hold it longer, but shift when you move the shifter.

[78 C10]

I just developed a similar problem with pretty much the same set up. It ended up being a vac line. Some how while adjusting the timing I knocked the line off. Also wouldnt hurt to pull the side caver off and lube the pivot points for the govener