That looks really nice, I need to do a new tank. I have a sump a friend of mine and I made that didn't turn out as we wanted it to. Its amazing the amount of baffling we have in the sump and you can still hear the pump change tone when you get on the brakes, even with lots of fuel. It doesn't cause a pressure loss but something changes because you can here the pump when you normally can't.
I need to work in a tank like you have made but under the car.
If you have no pressure change, I would say its just a sound change from the fuel load change on the outer walls of the tank, the Dampening change from front to back, just my opinion .
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
