70/05 stang

My brother is putting a 428 in his 70 sportsroof, it was a 302 car. My question is what rate of coil springs, shocks and leaf springs should he put on his car. Or anything else that it needs to make it handle good. He wants it to be a nice cruiser. He would like the stance to be level. It has iron heads, edelbrock intake and plans to move the battery to the trunk. Thanks for your help.