I made one for my 261 from the Tech Tips as well.
I bought casters from Harbor Freight that by rating (+-270 lbs each), should have worked... but in reality, did not.
I'd get better casters and also recommend swivels on all 4. It's much easier to manuever into a parking spot!
Jerry

1959 Chevy Apache 3200 Stepside
In the Stovebolt Gallery
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"A government that robs Peter to pay Paul can always depend on the support of Paul." ~ George Bernard Shaw