Anybody know where the location for the underhood light is for a 1967 impala?

 

Unless you're asking for an OEM original placement, then it doesn't matter, and if that is your question, I can't help you there.
But, if you're just asking for some light under the hood, they make some simple one screw/one wire addons, which have a tilt switch in them which light up any time the hood is opened. I had several of those placed over an excessively chromed up engine on one ride of mine in the past.