Try Joe at All Z East. You can check his posts on the forum and should be able to get his phone number or Email. If he doesn't have one Email me or post to the board. I have a couple and they were ok when the cars were parked (wrecked).
If Mike has a good one, give it a try. If not, I would suggest changing it over to an 82/83 style. You do have to change the oil pump/distributor shaft, but then everything is in the distributor, and it is easier to get parts for in the future. I sold an 81 CAS that was test run good, but apparently they returned their core one, trying to get credit, as the returned one doesn't have our marking on it, so I wouldn't send it out. I could possibly locate another one, as we are out of tested ones for an 81 only. Thanks, Joe 1-800-533-5659