At present time, the Facebook Online Store Application will allow you to display up to 49 items on your Facebook business page.
The reasoning for this is that anything over 50 products has the potential to timeout between your Facebook page and your store. Therefore, we kept the limit just under 50 items in order to minimize any possible connection problems that may occur.
As a suggestion, we recommend actually keeping the display amount to 48 products, since this would divide nicely into the column options available in the 3dcart Online Store App.
For example; a 3 column display will give you 16 even rows while a two column display of 48 products will give you an even 24 rows.