Exhaust cut-outs using ball valves?

I used a pair of gas filler necks under the front of the running boards on my
'34 Ford pickup in 1960.They were the perfect length to stop just under the lip and you could see about 1/2 of the chrome gas cap.Easy to grip and 1/4
turn off and on.They were the perfect wall thickness to weld onto the head pipe too! The paper gaskets leaked a little but you don't give a **** when you
are 16.I didn't have a drivers door window for a year,and the floor had holes
too,so exhaust leaks were less threatening...right?

 

Someone needs to build one.

 

i would think no matter what you come up with to seal it, i would think that their would only be a small amout of exhaust leakage at the cut outs due to that the exhaust would travel down the path of least resistance...out the back,

 

What about the cap of a jerry can? would it work? just go out and find 2 jerry cans and cut the cap of, you know the flip-thing, not the screw on type.
Sure they're only 2" or something but i recon it's enough.
They're traditional too, they've been around since ww2 right?