Back in the late 70's, I used to buy wheel blanks without centers from a place in Fresno, California and fabricate my own wheel centers out of flat steel plate for my dirt track car. I used a triangular gussset plate between each lug bolt hole for reinforcement. Ugly, but effective, and I could use any offset I wanted.

I've also fabricated rims using different centers, as you've suggested. The older centers for tube-type wheels are riveted, not welded, and they're relatively easy to remove by drilling out the rivets. Waaaaay back in the 40's and 50's, hotrodders used to "reverse" wheels by simply knocking out the rivets, and re-riveting the centers with the long offset toward the outside of the vehicle. That put the valve stems to the inside, so the wheels were smooth-centered.

Lathe-turn or grind the centers to fit your replacement wheels, and build a jig to support the center at the right height with the assembly set up on a flat workbench or a smooth shop floor. Tack-weld the center in place, and check for runout by mounting the wheel on a front spindle with a dial indicator on the flange. Adjust the runout as necessary before completing the weld. A brake lathe or a wheel balancer also works for this step. I used to stick-weld my wheels, but a MIG is probably a better idea.

Balance the wheels without tires on them, adding weight where necessary with the MIG to get as close as possible to perfect balance before mounting the tires. Good luck!
Jerry

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