exhaust design for try ys and oval pipe

[bryant]

My goal is to get 2 more inches of ground clearance. I want to take my long tube headers that hang far under car and get the collectors as close to the bottom.
Im thinking cutting the long tubes down and making them into a tri Y that comes to an oval 3" collector and use 3" oval pipe back to the mufflers.
Im sure it cant be as efficient as round tubing but is it a drastic efficiency loss?
Are their any tips to getting the most out of the tri Y design? Im going to be forced to join the pipes with how the current pipes line up so I cant optimize to the firing order.
Please any input on making the most out of this plan will be appreciated.

[TheJDMan]

I have never heard of any loss in flow between a 3" round or oval tube.

[dirty rick]

I would guess that not observing firing order would screw with the VE of some of the cylinders.