360 engine vibration

Not all TCs have drainplugs. No biggie, just crank some heat into the welder.The weights only need to be tacked on;but the tack has to be serious.If it flies off at redline, it will do a lot of damage.
You can remove the weights from a spare TC, by grinding off the weld.But note where it/they came off. They have to installed in a very specific location on your present TC,AND they have to be of a specific mass, according to what the reciprocating assembly dictates.In other words;you can't just weld on any weight, anywhere!
Furthermore, you have no way of knowing what your reciprocating assembly wants. If it is not stock inside there, it will want a non-stock weight welded on. So;some experimentation may be required. Or some research, by/from the former owner.The location to weld the weight on may not change significantly. But the mass may. You gotta start somewhere.