Question about Fender and Grill Fits

[Woz05]

I've been searching through the forums here to find an answer so I wouldn't have to ask but there is so much info here I probably just didn't see it.

What my dilemma is, is that i have a '70 GMC short box 4wd that I'm fixing up and I think I want to switch over the front end to a chevy front end. I know I would need to get a chevy radiator support since the headlights are different, but are the way the fenders are shaped different? or is it just cosmetic differences (like the marker lights or something along those lines)

So I guess I was hoping you guys could help me out by telling me what year Chevy grills if any would fit with GMC fenders. (I was hoping the 69 or 70 grill would fit it)

Thanks