Here is some cam information off of a camaro restoration website I found:

Shows all L48 from 1970 to 1973 as having cam part# 3896930 - .390/.410 lift, 310/320 (280/288) duration

Here is the link: http://www.nastyz28.com/2gcog/dtrest.html#einfo


And the search:

http://www.google.com/search?q=chevr...&ie=ISO-8859-1