The Haftorah on Shabbos Hagadol that falls on Erev Pesach:
The custom in these provinces is that when Shabbos Hagadol falls on Erev Pesach the Haftorah of “Veareiva..” is read.
 As it discusses the bringing of the tithes to the storehouses, which is similar to what occurs on Erev Pesach, being that on Erev Pesach of every 4th and 7th year of the Shemitah it is an obligation to bring all of one’s stored Maaseros to the house of the Levites. Now, although there are those which dispute and say that the time for this obligation is not on Erev Pesach but rather on Erev Shevii Shel Pesach, and so is the main Halachic ruling, nevertheless the widespread custom is like the former opinion. [ibid]