I just did mine today on a 67. Easy. Just pull the steering wheel using a puller I rented from O Reilly. Then pull old cam out. Cut and solder new wires and reinstall. No problem.
Seems like I have seen the 2-wire cams for ~$10 on ebay. My cars use the earlier "no wire" cams (SM9, I recall), which are ~$20, though I recall once using a 2-wire cam and it fit, just didn't use the wires.