This is what I've installed. I've only run my 261 for short periods before assembly and haven't fine tuned it yet but this distributor from Tom installed easily, looks great, got me up and running quickly. I'm excited to see how the engine performs once my truck is on the road finally.
http://www.langdonsstovebolt.com/store/#!/Ignition-Systems/c/18665949/offset=0&sort=normal
I used the square coil and had to build a little bracket to hold it on the side of the head. Not quite stock looking but I'm happy with it. Here is a quick video of my engine's first start up. You can see the bracket near the end when I shut it off.
https://photos.app.goo.gl/6xAX2z7CQFB0mqac2
