Is it possible to swap a 5.3 to a 6.2 in a 2005 Silverado if they have different 8th digit vin numbers?

 

Yes and no. Can you swap it, yeah you can. Will it work, no it won't.

It would not run if you did a direct swap. The 6.2 is a GEN 4 engine and not a GEN 3 engine like your 5.3 in that 2005 Silverado. The crank triggers are different, knock sensor placement is different, different intakes, cylinder heads, throttle body etc etc etc. All of that stuff would need a lot of work just to make it run and drive. Plus you'd need a custom tune just to get everything running.

 

^^ THIS ^^

The big difference is the 6.2 and other gen4 engines have a 58 tooth reluctor wheel on the crankshaft for the crankshaft sensor signal. The older gen3 engines have a 24 tooth reluctor on the crankhaft for that crank signal. The only way to make this work is to pull the crank out of the 6.2 and replace the 58 wheel with a 24 wheel. There is an adapter from Lingenfelter racing (TRG-002) that will allow you to run the 58 tooth crankshaft reluctor in your gen3 truck. The cost for the TRG-002 adapter box is $275