tires for 18" inch wheels for 49

[49tomchevy]

I have a 49 with ifs from late model 70's fullsize truck. I have had centerline build my front wheels 18x7 with 5" back space. This will bring the bare wheel just inside by about half inch inside the front fender. Backs are 18x8 with 5" backspace. I am thinking about 255x50 (28" diameter) on back and 205x50 (26.3" diameter) on front. Tires in picture are 255x70 on 15x8 wheels and have 28" diameter. I am hoping this will allow me to lower truck quite a bit without tire clearance problems in front.
No clearance problems with back.
Tom