No smoke to a Ton!

I bought this truck friday it has about 146k on it was drivong it home and it smoked just a little quite a bit on higher rpms but not extreme amounts. I left for the weekend got back sunday started it up and it started smoking very bad! It had no sign of moisture in the oil. I changed the pcv valve and it didnt help. Idk if this matters but its swapped to the weber carb. I know nothing about these trucks and would very much appreciate any help. I have seen people saying alot of them are because of valve seals. Thanks for any help!

Bad valve seals would only cause smoke for 10 to 30 seconds.

Start it and keep it running until it reaches operating temp. If the smoke stays heavy, then lightens up nearing temp, you most likely need a set of rings.

Welcome to the world of 150k oil-burning Mazda's. Classic symptom of worn out rings. It's almost a rite of passage if you have one of these trucks where the mixture control solenoid carb has started to not work properly, that excess fuel floods the cylinders, over time, causing the rings to wear out prematurely. The good news is that repair is not difficult, parts are cheap, and there are a lot of success stories on the board. Join the ranks.