I have a collection of short stories--48 in total, a word count of 80,000 and 156 pages. Regarding publication, is such a collection likely to be too large? If I were to split it into two collections, is it likely that I would receive a more positive response from a publisher?
Publishing a collection of short stories is a difficult matter in general. Usually, if a collection is published all, or almost all of the stories will have been previously published and at least one in some top-tier publication such as The New Yorker, The Atlantic, The Paris Review, Granta or Virginia Quarterly Review. The only recent instance I know of where a collection of previously unpublished short stories was published by a major publisher was Someone Who Will Love You in All Your Damaged Glory by Rafael Bob-Waksberg who had the advantage of a significant platform courtesy of being the creator of BoJack Horseman.
So step one is to get the individual stories published. Then, once that's happened, you can maybe find a publisher. Even that's difficult. Most debut short story collections come out from smaller presses and often through contest submissions. The good news is that if you can publish all or most of the 48 stories, it would put you in a good position for submitting.
Are you going to self-publish? Then you can do anything you want to. Don't expect many sales unless you have a following already.
Are you trying to find an agent or contacting traditional publishers directly? Then you should look at the guidelines they show for your type of work. But again, if you are not well-known and/or don't have a big following, your chances of being published are small but not impossible. Or do you have a track record of being published anywhere? For example, a pulp magazine with short stories, or even a university press or some other literary publication?
Short stories tend to not sell as well as novels.
And some genres do much better than others.
What sort of stories are they?
Your best bet might be to investigate true self-publishing (not one of the vanity presses claiming to be self-publishers) and DIY while focusing on learning marketing and building a following on social media.