You should have two pipes from the manifold back that merge together at the catalytic converter and one out into the muffler. You can cut the converter out and run true duals with two new cats and two separate mufflers which will give you the best sound imo. And 4.3 is v6 5.0 or 5.7 in v8.
yeah broskeeee...
straight from wikipedia
L99 (4.3L)
A 263 in3 (4.3 L) was based on a 305 in3 with updated block architecture to be Generation II and a reduced 3 inches (76 mm) stroke. It was designated the L99, and was introduced in 1994 for the Chevrolet Caprice. It was externally identical to the LT1, but the bore was 3.736 inches (94.9 mm) and the stroke to 3 inches (76 mm) giving it a displacement of 263 in3. The pistons used in the L99 were the same as the ones used in the Vortec 5000, but 5.94 inches (151 mm) connecting rods were used to compensate for the shorter stroke.
Like the LT1, it features sequential fuel injection, reverse-flow cooling, and an optical ignition pickup. Output is 200 hp (150 kW) and 245 lb·ft (332 N·m). Due to its smaller displacement, it provides better fuel economy than the 5.7 L LT1, but at reduced horsepower & torque levels.
its okay.. i've been wrong before..