Gen Iii To Gen Iv Replacement

[Guest pjblurton]

I have a 2003 Silverado with the Gen III 4.8L and 200,000 very well cared for miles. My heads have finally started with the porosity cracks and gradual loss of coolant (TSB 06-06-01-019B). Rather than put new heads on a high milage engine, I would like to replace the whole thing.

I have found a reasonable deal on a new and complete Gen IV 4.8L. Including intake, ignition coils, fuel injectors, exhaust manifolds, plugs, plug wires, etc)

My question is this;

Is the GenIII to GenIV swap fairly straighforaward? I can see that there may be a harness or two that would need to be changed and would expect that the PCM would need to be re-programmed, but if there is anyone on the board that has done this swap and can they relate any experiences or advice, it would be greatly appreciated.

I'm not interested in hearing, "drop a 6L in that puppy and let 'er rip".... just accurate technical advice related to the original question.

[Guest pjblurton]

of note: This NEW engine is the only one that not have AFM or VVT...

[Guest pjblurton]

May be a non-issue... I found an even better deal on a N.O.S. GenIII