My new 75 Duster stocker, let the fun begin.

Cool! Where is "Edson"?
You may be in a "hornets nest" in Stock, probably between E/SA and G or H/SA, but that's what the car appears to be set up for (9" tires. Like the Holeshot Wheels. They are kinda local to me.). SS may problematic with the higher maintenance & if you have budget concerns. But best of luck either way. Looking forward to more pics & info.
Edson is in Alberta Canada. The car has raced in both G/SA, and H/SA, and most recently was very competitive in SS/JA. I will likely buy the stocker engine as that is most realistic for my current budget. Will also get the Protrans 904 that was with it. I have a very steep learning curve ahead of me, but have a very nice platform to work with.