You may have a head gasket just starting to fail. When mine went I hit 196 after idling for 20 minutes otherwise it ran fine. It was just enough over pressure to dump coolant out of the the overflow. The gasket had a hairline crack.

As to the lifters, you can get them out fairly easily. No need to remove the heads, it just takes a few 4 letter words and some finagling. I used a pair of circlip pliers to apply pressure on the inside and ease them up and check them when I did my heads.