Sorry for not being specific about what type of trucks I am trying to convert...but, yes...3-rail freight car trucks to 2-rail.
Normally, I'd just slap on a set of Atlas O trucks...that you can easily purchase...but, I want to preserve the original truck side frames as they have the car's reporting marks on them.
I've twisted and twisted to no avail...I'll send an email to Atlas O and see what they say tomorrow.
Could this lack of conversion ability be why they actually sell the entire truck??