Yes, we installed the hinged door, guide bar to prevent the flop tube from hanging up, etc. Bruce Hill helped me with this project - he actually did most of the hard stuff. Everything was done exactly according to plans. And I know that the flop tube is working as it should because I can stay inverted much longer than before the flop tube install. Before, the engine would hesitate while inverted after about 7 seconds or so. But I think I know what the problem is. Now that I think about it, the problem is always worse when I fly with very little fuel in the tanks. What is happening, it seems, is that while inverted, the fuel gets drained out of the inner bay (the door helps to keep the fuel in, but it's not a perfect seal, so after prolonged inverted flight, if there is little fuel in the tank, it will eventually all drain out anyway). And when I roll back upright, there is no more fuel in the inner bay and it takes time for it to come back, which is what's causing engine hesitation for a few seconds before enough fuel gets drained back into the inner bay to be picked up by the flop tube and sent to the engine. I'm quite sure this is it! I will go and test to confirm this and report back. Thanks!