I don't have access to a '67, but maybe you can get a rough idea on placement by looking at photos on the Internet. Just do an image search for '67 GTX's. Maybe you can Fake-in the placement from a photo. I've done that before.
A Factory Body Service Manual may show placement if you can locate a copy.
Maybe you can do a Member search here on Moparts and look for GTX owner related names.
Or, attending a big Mopar car show may yield a car to get your measurements.
Example, The Chrysler Nationals Mopar Car Show (2,500 Mopar cars) is this weekend (July 10-12, 2015) in Carlisle, Pennsylvania. Bet there will be a '67 Belvedere GTX there at the show.
http://www.carlisleevents.com/carlisle-events/carlisle-chrysler-nationals/default.aspxAlso, if you don't get an adequate reply to this post, maybe you could start another with a different Topic line, like, ," '67 GTX Emblem Placement?"
