Darn, I got this far before making a rookie mistake, not bad I guess
The OD was 13.08, but even after heating the heads to 400 and freezing the guides, they would not go in. I actually ruined the first two that I tried. After turning them they still took decent hits to get them in. By no means did they tap right in. I think (hope) the fact that the stems won't go in would indicate pretty good crush, I just didn't expect that but it makes sense.
John, I'll send you a PM later to discuss your services. I appreciate the help here. I think it's time to let a pro take over.