850 thermo quad

if you're talking about the plastic caps on the bottom of the plastic bowl, under the primary jets, that's somewhat common. I don't know for a fact, but I think it's from soaking the bowl in harsh cleaners for extended periods. it should only take a quick rinse in mild solvent to clean the plastic bowl.
Yes ...went well ..carb was soaked and blasted from a friend..it looks brand new!!! And another weird thing is car started leaking 50 to 100 miles back on oil pan rear and was only little bit in back..now no leak..did the gasket possibly swell back up and re seal???