This is the kit I used on my last build. The 71 style black plastic headlight bucket retainers will not work in a 70 grille, they are to tall. Also, the x3 black plastic round push pins for the lower valance insert also will not be used.

https://www.ebay.com/itm/Mopar-70-Cuda-Barracuda-Grille-Fastener-Kit-Screw-Grill-1970-NEW/401791467507?epid=5013273842&hash=item5d8ca33ff3:g:ibcAAOSw2QZdC9i1:sc:USPSFirstClass!44253!US!-1