Dan, I should have weighed the car with the V6 installed but....I’m just not that smart.
I would estimate my LS1 4L60 combo is at least 175 lbs lighter than the V6 ST300 combo. The new power steering assembly is 20 lbs lighter, the LS plastic intake with injectors is only about 5 lbs, and the starter is much lighter. The engine block,heads, pan and brackets are aluminum, and the exhaust manifolds are lightweight.
Would you think the V6 might be 75 lbs lighter than the 300 V8?