Summit Cam Help/Recommendations

So we've got a little change of plans. I popped the heads off this weekend and it looks like the bottom end is junk. Cylinders are super rusty and the pistons won't move much without excessive force, even after letting the motor sit with oil in the cylinders for a week. We knew it didn't turn much when we bought it, but at the end of the day it was still super cheap and we figured it would free up after letting it sit with the oil. Although I don't think I will be able to get it done for this summer anymore as planned, I still think this is a good opportunity for me and my buddies to really dig into a motor and do our first complete rebuild.

With that said, I have some new questions, beginning with how cheap can I get away with a rebuild? Ideally I'd reuse everything possible, but if that's not feasible, I understand. I also understand that I don't want to go completely cheap and put some money in good parts, but I also want to keep this pretty budget friendly. I found some rebuild kits from Mancini that aren't ridiculously expensive, are those any good? One of them even comes with pistons, so that may be helpful if that's necessary. I figure I'll probably need to get the crank cleaned up somehow too? I've never really thought beyond a cam swap before, so this is all gonna be really new to me. Any advice, words of wisdom, or ideas are greatly appreciated.

I guess this means I can broaden my cam choices a little though too lol