Alignment issue or other problem?

[agnes the dog]

I recently swapped my stock front axle for a 3" drop axle. In the swap, I also changed to much newer spring packs and a much stiffer tie rod with newer style ends. I used the stock drag link and steering arm. The truck tracks straight down the road until I give it moderate throttle, then it will pull significantly to the left. Letting off the throttle after that will cause the truck to pull back to the left. Is this an alignment issue or am I feeling bump steer? I have not yet taken the truck to get an alignment done mostly because I don't want to have to pay for another alignment if I should be looking elsewhere in the steering/suspension first.

The truck did not exhibit this symptom before the swap, so I'm assuming that I have created this condition somehow in the swap. The old springs and bushings were worn out badly, perhaps masking some condition?

I do have an adjustable drag link that came with the parts deal, but it appears to be several inches shorter than the stock drag link. Does length matter (referring to drag link, haha)? With the adjustable link, I could simply flip it to the bottom side of the steering arm and most likely get my drag link more parallel to the frame. I didn't want to try it since it was so much shorter than the stock piece.

Any help would be appreciated. This is my first attempt at steering/suspension mods, so I'm just learning about this stuff. Couldn't find what I needed in a search.

JJ