I believe .25", is there thicker?
I kinda envision the following (see attached photo), red represents the current TB bore shape, grey represents two pieces of pipe roughly an inch long stacked and offset. Blue represents the material the "cut line" to give it that funnel shape.
This would take a chit load of time to shape by hand, all I know is if I had access to actual machines Id be dangerous and this would amount to a lathe and shaping the pipe outward vs me trying to carve it.


If anyone has a better idea or cheaper source for preshaped velocity stacks, Im all ears. Can be used pieces, Id rather spend the time bringing an oxidized piece back to life than trying to create this.

Just needs to be aluminum, as Im gonna probably braze it to the existing aluminum TB and make it appear as if the factory did it.