Picking up an old Bracket car. Have some questions

Any belts are OK to 11.49. Faster than that, the belts must be certified/dated.

A roll bar is the same, if it's 11.49 or faster, it needs to have a rool bar that meets spec. Slower, it requires no roll bars. What you have should be ok.

Battery in trunk, needs a bulkhead of .024 steel or .032 alum.

Listen to what cracked tells ya.