Milt... they have diesel model engines now also.
The box is for an Enya 60-4C. .60 is the size, 4C is 4 cycle.
The 60-4C came out in 1982. More interesting stuff here:
http://www.rcmplans.com/issues/requested/content/reviews/pdf/r-rv-enya120-011988-1-1.pdf
Google pulls up prices that range from $75 to $280.
I'm sure condition and documentation affect the value.