Trivia: When did Superboy and Lana Lang first kiss?

[The Time Trust]

Hey all,

I've been trying to find the first instance in the comics where Superboy and Lana Lang are shown to kiss. The earliest instance I've noticed is Superboy #143 from December 1967, in a story called "The Big Fall," but it seems a bit late to be the first time they're shown to kiss. After all, Lana Lang was introduced in the early 1950s.

So which issue and story did Superboy and Lana Lang first kiss? Anyone here know, or do I have to track down John "Mikishawm" Wells for this bit of trivia?