1974 Duster slant car---- big bolt pattern wheels, discs up front??

Yep, my ‘74 Duster was a /6 with BBP disk brakes. Very few other options.

73+ drums were still standard with a /6, and if the car had 4 wheel drums it was also SBP. But if it got the disk brake option it was BBP. 73+ all v8’s got disk brakes standard. And there were several other option packages that would trigger disk brakes on the /6 cars as well, although they could be added as an option by themselves.