No you won't need an electric fuel pump. The ZZ4 has the standard provision for a mechanical pump. You may have to buy a new fuel pump rod though.
And yes, a 350 TH will work great behind your ZZ4 and will bolt right up.
I've been running a 350 TH out of a 76 Camaro that has seen two years of 1/2 mile dirt track racing before getting installed in my car behind my ZZ3 with nothing more than an oil change, shift kit, and a new converter.
It has also seen many dry pavement 2nd gear burnouts as well.
Bill