Hi Scott,
it this bunch of classes that Woo uses for its shop product titles – it currently has 0.5em vertical padding. Adjust as you see fit:
.woocommerce ul.products li.product .woocommerce-loop-category__title,
.woocommerce ul.products li.product .woocommerce-loop-product__title,
.woocommerce ul.products li.product h3 {
padding: 0.5em 0;
}
Alternatively you can adjust the bottom margin on the image with this selector:
.woocommerce ul.products li.product a img