Datsun 510 exhaust. Dude you gotta call this guy. Mike in riverside. He got me a kick ass exhaust manifold for my 1970 datsun 510. I don't have his number right now, but if e-mail it back I'll get it for. I paid like $140 including shipping.
Some advice though. There is a flange where the manifold meets the exhaust. Save yourself a huge headache, and request an exhuast shop to cut those out with a torch, (while it's out of the car) and put nice new fresh bolt in them, and then rebutt the flange with a new gasket. Those old manifold are casted and easily cracked at those bolts. I went through two till I figured out it's easier to just tap them out.
as far as the rest of exhaust, I found it easier to just custom from the manifold back. I had a glass pack on there but didn't like the sound too much, so I changed it to a Magnaflow. Sounds Nice now.
remember. you will butting old stuff with new stuff. You will need all the strength you need, to avoid an exhaust leak