I suppose you want do simulate the LOOP GAIN, don´t you ?
I suggest to place an ac source between opamp output (out) and the feedback path (in); thus the dc bias point is preserved and you can do the ac analysis.
The loop gain then is simply V(out)/V(in).
This method has only a very small loading error, however, as the opamp output resistance is low and if the feedback path has a higher resistance at least by a factor of 10, the error can be neglected. In any case this method is better than the "big L and big C" method.