Stepside bed inner wheel tubs

[redsled87]

Has anyone added fleetside wheeltubs to their step side? Mine sits fairly low. I was going to go the whole way into the frame rail in case I want to go bigger in the future. I'm running a 325/50/15 drag radial on a 10" wheel. I've got about 1-2" of gap to the wheel opening from the tire. I'm looking at running a wider 30-31" tall Hoosier Quick Time Pro tire. Can't hurt to have more tire with a torquey big block! Just wondering if I'll be fine with factory tubs or I need aftermarket ones. This is on an '87 by the way. Thanks