To start off with I bought a felpro no retorque head gasket! But to be sure should I retorque it after driving for a while and after how many miles, also when should I retorque the manifold nuts?

It never hurts to recheck torques. In certain areas rechecking fasteners torque should become part of your regular maintanance program. A few hundred miles after the installation of a new head gasket (convensional type) is a good general rule of thumb for retorqueing the head bolts.....same goes for the int/exh manifold fasteners. As a general pratice and since no disassemby is required, rechecking the torque on the int/exh fasteners is relatively easy to do and should be checked occasionally.