That design of wheel has an edge-locking full circle ring with a very narrow locking surface that is susceptible to rust damage. They're not as dangerous as the center-split "widowmaker" rims. I ran them on a 59 3800 and it was difficult to get the lock rings to seat properly during inflation. If you can find a good set of 19.5" tubeless tires and rims, it would be a better choice than trying to run the 18" tube type tires. That size rim was used quite often on step-van type 1-ton chassis bread trucks. If there's a bakery near you check to see if maybe they have a stockpile of old wheels stashed away.
Jerry

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