What did they do to get the hp boost for the Gen2 cars?

[Nuck]

Was it a bunch of here and there tweaks or was there some major internal changes?

 

[Nadine UK GTS]

For starters they improved the cooling system and raised the compression ratio slightly, GenII has different engine castings with cross bolted main bearings; the motor was something like 80 lbs lighter. Changes to ECU.

 

[Jack B]

Injectors, headers, exhaust system, cam, PCM, compression, heads and coil packs were the major changes. The Gen 1 rated hp (400) was lower than reality. The Gen 1 also had a a very restrictive exhaust system.

 

[Performin Norman]

Is there anyone that can do PCM tuning or are they just preset parameters?