I did some research on the bird related brands not too long ago, I was interested in Golden Eagle gas. I've never seen Blackhawk before. I zoomed into the image to check it out. I can make out BLAC - - AWK. The center portion also says something thats not the typical ethyl logo. I'm assuming bottom says ethyl, hard to tell.
In the past I've taken the thinnest paper I can find and made a rubbing with a pencil lead to figure these things out. M ight work on this one,