Is my torque converter messed up?

[72firebird]

Well I decided to take my car to the track this last Friday and everytime I reached about 85-90 and the torque converter locked the car would pulsate about 300-400 rpm the rest of the way until like 110 when I let out. The torque converter is a brand new Pro Toque 3000 stall l/u, I have put only about 1000 miles on it and the transmission. Could this be the torque converter not staying locked or it slipping? I don't know really anything about automatic transmissions which is why I just had it built by Vince and told him how I was going to use it.

 

[72firebird]

Well I just talked with Vince Janis and he said it sounds like the torque converter solenoid. How easy will this be for me to change? He says you just drop the pan pull the filter, and then cut the wires and pull it out then take a punch and push up in the hole it goes into on the pump and make sure it goes up and down without sticking and if it is smooth the pump is fine and just replace the solenoid. He also said for me to use a universal solenoid. Are there any suggestions for what to get so I don't ever have to replace it again? Also if anyone has a good write up on how to change it please post it.