Stroker Performance Review

I fell for that GER add too. I put a "3000 stall" in my dead stock (except for a full manual valve body for the column shift) A12 car.
It stalled 4300. I could drive down the road at 3000, not move my throttle foot, and put the car in any gear, the speed and rpm would not change.
If I had to guess, I would say 20% slip. Maybe more. The car was completely undrivable.