Dear mohadese
Hi
As i understood you want simulate internal circuit of a 741 op amp in pspice . when you are talking about what transistor should be sued , it is important to know , specification of transistors are pretty important . e.g maximum and minimum beta of transistors , maximum value of IC of them ( as you probably know in each opamp there are at least one or two current source , so , the current of current sources , has relation with specifications of transistors . ) and .... etc .
Hence , i think you should find a circuit to follow . ( value of all of components are pretty important ) . there are many circuits available in text books , did you tried ever ?
Best wishes
Goldsmith