Yes, just plan on swapping all of your sensors, distributor, accessories and brackets, etc....
Look in your glovebox for the engine RPO code, for 03 it should be LU3 but could be LG3, the only real difference is the improved injectors, which you now have installed in your blown motor and the LU3 had the "quiet cam" in it. Same lift specs and all, just profiled differently to keep the lifters in contact with the cam during ramp down.
2002 saw major changes to the 4.3L fuel-injection system. For 2002 California emission Chevrolet Astros, GMC Safaris, Chevrolet Silverados and GMC Sierras (This includes S10's) all came equipped with the updated LU3 4.3L. 2003 saw the L35 discontinued and the LU3 replacing it in all other applications. A new variation was also introduced in 2003, the LG3. For 2004 to 2009 the LU3 has been the only 4.3L produced.
The biggest change to the LU3 and LG3 was the fuel-injection system. These engines used a multipoint fuel-injection system, with six Multec II fuel injectors mounted at each intake port on the manifold. The composite upper intake manifold and cast aluminum lower intake from the L35 engine is also used on the LU3. The LG3 uses a cast aluminum upper intake and a cast iron lower intake.
The LU3 also received a quiet cam to help reduce vibration at both idle and high engine speeds. This camshaft used the same lift and duration as the older design, but the cam was reprofiled to keep the valve lifters in full contact with the cam lobes as the cam ramps down.
The LG3 was used in Chevrolet and GMC S-series pickups and was only produced for 2003. The LU3 was used in the Chevrolet and GMC full-size trucks and vans, the Chevrolet Astro and GMC Safari vans and the Chevrolet S-10 Blazer and GMC S-15 Jimmy. The LG3 was rated at 180 hp (130 kW) and 245 lb·ft (332 N·m) of torque. The LU3 was rated at 190-200 hp and 250–260 lb·ft of torque.
Year Horsepower Torque Fuel System Compression Ratio RPO Applications
2003 180 hp (130 kW) at 4,400 rpm 245 lb·ft (332 N·m) at 2,800 rpm MPFI 9.2:1 LG3 5
2003–2005 190 hp (140 kW) at 4,400 rpm 250 lb·ft (339 N·m) at 2,800 rpm MPFI 9.2:1 LU3 3,4,6
2002–2003 200 hp (150 kW) at 4,400 rpm 250 lb·ft (339 N·m) at 2,800 rpm MPFI 9.2:1 LU3 2
2002–2003 200 hp (150 kW) at 4,600 rpm 260 lb·ft (353 N·m) at 2,800 rpm MPFI 9.2:1 LU3 1
2004–2009 195 hp (145 kW) at 4,600 rpm 260 lb·ft (353 N·m) at 2,800 rpm MPFI 9.2:1 LU3 1,2