proper offset for wheels?

anyone know if a 40mm offset will fit inside the bed arches in the rear without having to machine the hub of the wheel

Depends on width.

it would be an 18x8 wheel...

russ-d told me for an 18x8 on 2 wheel drive metal you need a + 50 and a 18x7 you need +37 thats the numbers he gave me anyway hope it helps

thanks guys i appreciate it i guess if they dont work i can always take them to the machine shop and knock off a few on the center hub of the wheel