I ended up buying these for $25 and change

Amazon Heavy Duty Casters

500 lb ea load rating for 2000 total- these were the best combo value of price/load I found

So I'll have both the DIY cart and the Metal One linked in first post


'51 Chevy 3100 Truck - OEM 216 Engine; three speed column shift transmission
6 Bolt disc conversion with dual master/vacuum booster
12V alternator conversion.
235 engine in waiting grin