Why swap to Gen III engine parts?
They make more power. The Gen3 cylinder heads have flow ratings from GM Performance Parts of: 16.7% more flow on the Intake port of the cylinder head due to revised port design. 31.7% more flow on the Exhaust port of the cylinder head due to better port design and a new revised “D” shaped port The Gen III Lower and Upper Intake manifolds are also the key to increased performance. There are two sets of different style Lower intake manifolds and corresponding upper Plenums. Both of which flow more air and increase performance compared to the very small diameter and radius runner Gen2 manifolds. Combine this with Gen III exhaust manifolds, with more potential to flow and you have a good combination to gain a lot of power from your Gen II engine block.
