Having been inspired by the marvels of flying the YA-7E and presented with the opportunity for a very economical program through the conversion of existing A-7A and A-7C airframes, the Navy placed it’s initial order for three airplanes in 1975.  While recognizing the airplane’s value as a combat trainer, the natural appeal of the airplane as a two-place combat machine did not go unnoticed.  The US Navy chose to produce the airplane equipped with the full complement of A-7E avionics.  Powered by the existing TF-30 engine, it was another LTV bargain.

The TA-7C took a long time to happen, considering that the initial design was in place in 1965.  Some management differences of opinion prevented any serious effort to the two-place airplane for at least 2 years

A-7:

Genesis of the Navy Attack Bomber, Light (VA(L))
In Comat
Farewell Proud Bird
Aircraft Performance Perspective