Lost your email so I posted the film here so you can see how I was able to follow you up in your vertical climb and get you as you rolled over to come back down.
First off, you'll notice that you started your vertical climb at a little over 300mph and not 450mph like you thought and I did not immediately follow you up. After I came over the top of our merge, I was around 250mph and when I leveled out, I dipped my nose down slightly until I got to around 300mph. This is when I finally pulled up into the vertical and followed you up. At this time you'll notice that your speed was burning away fast as you continued your vertical climb. This let me close the gap some more because this is where the P-38 has a clear advantage over the P-51. When you finally came over the top of your vertical maneuver, you were down to 159mph and not 300mph like you thought. Since the P-38's vertical performance is better, all I had to do at this point was just roll over as you started to come down and fire was you were passing in front of my nose.
The reason I was able to pull this off is because I took advantage of the better vertical performance of my plane and you played right into it. Now had you gone into a spiral climb instead of a vertical climb, you could have taken advantage of the better climbing ability of the P-51 to counter the better vertical performance of the P-38.
Anyway they were fun duels against you and SHawk
AKAK P-38 vs. Caps P-51D
Ack-Ack