LSx Valiant Build. Take a look inside...

So what kind of mileage does he get?
I believe he was pulling about 19 before his Aeromotive pump went out. Then on the way back, with the bed fully loaded (including a flat head block) it was down to around 9 or 10. I can ask him again, but I'm pretty sure it was around that.

What is what the fittings on above the ones with the lines?

Well, about them fittings... This particularly fine pan has this fun little block on it that would allow you to run the lines either down or off to the side. The excellent engineering in this piece didn't allow for the fact that the fittings and the plugs run into each other before the threads seal. Fun ensued. What is it I say about swaps never being plug and play?