If you are going to rebuild heads for your 305 casting 14014416 1.84int 1.5 ex is it a good plan to make the valves larger for more HP?

Often times, installing larger valves produces better top-end horsepower at the expense of low-end torque. Bigger valves may require rethinking the entire combination: cam, compression ratio, rear end gear ratio, torque convertor, etc. Also, sometimes adding larger valves has no effect at all since the valve opening may not be the limiting factor.