Are there risks to taking 324mg aspirin/day following stent surgery consecutively for 5mos? I would like to know if this is normal/safe for 65yo male

Sometimes. Daily Aspirin at 325mg/day can cause gastritis and bleeding from the stomach. Many experts recommend the high dose for the first month and then 81mg daily after. The lower dose has good effectiveness and may be less likely to cause stomach bleeding. Patients with stents need daily Aspirin for life. For the first year after a stent, drugs like Plavix (clopidogrel) or Effient are essential to prevent stent clots.
81 mg. Following coronary stent placement most physicians recommend Aspirin (81mg) for life. Taking larger doses of Aspirin isn't of benefit but will irritate your stomach more than a baby aspirin. For uncoated stents one month of a second anti platelet drug like clopidogrel (plavix) is recommended. If you have a drug coated stent, usually one year of the second anti platelet drug is recommended.
No, for most. Full doses of asa are fine, but most will be tapered to a baby asa dose of 81 mg/d or 162 mg/d asap since efficacy similar, with reduced risk of GI bleediing or upset. The Plavix (clopidogrel) or Effient agent is as important. Talk to your doctor to clarify.