I want to transfer $290,000 of my post-tax money to a bank account in Brazil I just opened to purchase a home there. The entire deposit will be used to purchase a home there. I will obviously file the FBAR form 114 with the IRS next year when I do my 2019 taxes. Any tax implications since the money comes from my U.S. personal bank account and is post-tax money?
There are no tax implications in the US for this transfer.
(I don't know for Brasil, but doubt there are any).
Depending on where the money came from (gift, investment sale, house sale) there could be taxes due - but that is unrelated to the international transfer.
Worst case, the IRS could get interested where the money came from - if you deposited it in cash, that might raise some flags... But if it is legally earned, you will have no issues.