I made mine with the plastic tubes from two cotton swabs. I found some styrene tubing that fit nicely over the tubing from the cotton swabs and I cut it to the length I wanted and rounded the ends. After sticking the two together, I flared and angled the inlet and outlet pipes, painted and weathered them.
The brass item is the driveshaft. I had lengthen it because I lifted the rear of the car.
Since I made them with workbench scraps, I don't have any specific information on the materials I used. Hopefully, this will give you one more idea to work with.
Regards,
David G.