Loren Ver,
As mentioned by the other post, your donation will not increase your MAGI and, if you already file Schedule A, it will reduce your both your AGI and MAGI, so should your ACA calculations.
The donation limit will be based on your AGI (in case this is different that your MAGI). Depending on the organization, your limit will be either 20% or 30%. Stock is considered a non-cash/check donation. If you sold the sold (creating a capital gains event), your donation limit would increase to 60% of AGI, but you may also have capital gains to report.
If your AGI and MAGI are the same, your limit will be 30% of $32,000 - so $9600. That means you will have to carry-over $55,400. And, as mentioned, the carry-over is for only 5 years, so you will not get the full benefit of the deduction unless your AGI increases in future years. All things staying the same, you will miss out on deducting $17,000 of the $65000 donation.
Given the timing of your question, you may want to spread this donation out across multiple years so you do not loss the deduction in future years.
Have you considered a DAF?
Best,
Paul