However it does not say that the 4.3 block's are different but the cooling system is different, that would probably affect being able to interchange the two.Trancer said:There was an article done in Truckin Magazine about this... The engines are not the same. Ok found it... Its in the July of 2003 issue. Here are several things that are different...
Heads, exhaust system, cooling system, engine operating ranges, internal engine components, camshafts, Compression ratios, cylinder heads, intake manifolds, fuel system, ignition, starer motor and alternator.