latest problem

I had a similar problem with my 65 Barracuda as I was trying to maximize my full-throttle upshift speed to around 4000-4500 RPM. I started playing with it a long time ago so I don't remember all of the details but I ended up with an overadjustment which caused weird 2-3 and 3-2 shifts. With my 1bbl Carter BBS, it seemed like I had a fuel starvation problem at high RPMs. With the AFB (and an electric fuel pump), I still had an occasional loss in power when I mashed the gas pedal but I would also find that my transmission would kickdown into 2nd gear at 70+ mph.

As I was attributing this behaviour to internal leaks, I figured this problem would go away when I got around to rebuilding the transmission. However, on a whim one day, I decided to readjust my transmission linkage. With a few turns, the problem disappeared without any real impact on my upshift or kickdown speeds.

Double check that everything looks properly reinstalled and back in its original position. You might need to make some adjustments to your transmission's throttle linkage. A service manual is what you need to properly make those adjustments. BTW, I can't seem to find the posting that specifies what kind of car you have.