When you are flipping property, the transaction is a dealer disposition. All of the potential profit is taxable as ordinary income in the year of the sale, even if you have not received all your profit yet. Additionally, the sale profit is subject to self-employment income taxes.
Dealer dispositions are not allowed to use installment sale tax treatment. Flipped property can not participate in a 1031 tax deferred exchange, and, capital gains tax treatment does not apply.