New Project - 70 Chevy C10

[rjdutch]

My name is Rob and I'm new here though I've been following the forum for some time. Just picked up a 70 C10 that I'm getting ready to tear apart and restore. It's a basic model, no power anything and a bit rough. It has a 305 (1986) and a THM350 trans, both getting removed. Ordering a 290hp 350 crate engine and a new trans. Lots of sheet metal work. As of now I plan to add disk brakes and lower just a bit. Nothing over the top, I just want to make it tight and strong. And add power steering.
Question:
The previous owner had installed new rockers and just riveted them in. Can I grind the seams and weld them? Or should I remove them and cut them in?
Thanks and I look forward to soaking up all the awesome knowledge around here.
First of many pics: