[jonmc56]

Here's the search string I typically start with on CL (in the 'auto parts' or cars+trucks' for sale category):

(67|1967|68|1968|69|1969|70|1970|71|1971|72|1972) (chevy|chevrolet|gmc)

Inside the parentheses are the terms I'm searching for, the vertical bar means "OR", example: 67 OR 1967 OR 68 OR 1968 etc

If this returns too many results you could add this to the end:
(pickup|pick-up|"pick up"|truck|c-10|c10)

Note that there must be a space between the groups of parentheses.

You can also fiddle with "search titles only" and "include nearby areas" to expand/reduce the search.

HTH,
Jon