So I'm finding out that nothings gonna be easy with this truck. Since its new to me, I'm doing some normal tune-up things. Not sure when Grandpa last did much to it. It's a 235 and the book says use 10mm plugs. It currently has Champion UY6 plugs. I'd like to use ACDelco and I get several when cross referencing but it looks like maybe the M8 is the one? I've seen people suggesting the R43 but that's a 14mm plug...maybe for the newer model engine. Any suggestions? When I look the truck up at different parts stores I don't get the option for the 2 ton loadmaster. 1 Ton seems as big as it goes. I would assume the 235 Chevrolet made for these trucks are all the same right? Whether it was a 2 Ton or a 1/2 ton. The wires need replaced as well.