Hi,
One option is to look at one or several manufacturers' websites on the actual product page and check if there isn't a model version or several to choose from you can use. I use Tina-TI, the models I add from them and other manufacturers are often PSpice versions already but for some reason I'd thought they were valid for LTSpice too, maybe I'm wrong on that one as I haven't tried.
If you need to and want to try, there's a way of converting PSpice models to LTSpice. I don't know if it's a procedure which is hard or easy to follow. It looked relatively simple with only a few steps once you get the hang of it. Analog Devices have an online tutorial/app note about it. It's such a common device there must be several models.
A relatively longer approach if you don't find a model would be to join TI, download the free TINA version, and use the ready made model of the 4069, or the model of the 4049. It also has the model for the SN7404, TTL but still could be of interest. To simulate oscillators on the free version you sometimes need to change three analysis parameters - should you ever want them, let me know and I'll upload the relevant info I found to save having to search yourself.
Hope you found a model, anyway.