Differences in years?

**Semperfiws6** · 12-29-2007, 01:32 AM

I am planning on buying my wife a GTO but dont really know too much about them. what are some of the differences in the years? any weak points between the years or manual vs. auto tranny? I know the 05 and 06 has nore power than the 04, hood scoops etc., but im looking for a little more in depth factors. any help would be appreciated.

**Sarge** · 12-29-2007, 05:15 AM

The most obvious change is the new LS2 motor that for the most part everyone knows about, same as the 2005 Corvette. Larger bore LS1 based motor with new cam sensor and knock sensor placement. Larger intake and throttle body. Static Compression Ratio is raised and the heads are revised LS6 '243' heads. The 'E40' PCM in the 05 is brand new along with the drive-by-wire throttle body system. The traction control is not as much of a “push back” system anymore. Traction Control is now managed with spark, brakes, and cylinder cutout. I experienced it and it seems to cut more timing then last year. The new PCM is located where the coolant overflow tank resided on the 04. The area between the frame rail and the driver-side exhaust manifold now has much more clearance. The coolant overflow tank is relocated to somewhere below/in front of the air induction box. The ABS system is a new Bosch 8.0 unit with electric brake distribution. The front setup comes from the Corvette style 40.5 mm twin piston calipers and 320 x 32 rotors. The rear calipers were also painted to match but are the same as the 2004 GTO, however the rear rotors receive a slight upgrade from a non-vented rotor to a 286 x 18 vented rotor. The Master Cylinder is an improved 25.4 mm unit along with an improved 8"x9" booster with a dual reaction ratio ("Brake Assist") designed to give a better apply rate above 0.5 to 0.6 g deceleration. The exhaust is very different in 2005 with new manifolds that have less restriction along with a crossover resonator and dual exiting exhaust. The mufflers were said to be less restrictive as well by a small percentage. What was surprising was the fact that the drive train was also upgraded. This does make sense, with the added power output. The pinion gear is stronger, there was a material change and it is shot peened. The CV Joints are from the HSV parts bin from AWD VZ range. The interior remains mostly unchanged. The font in the gauge cluster is more italicized then before, and there was an addition of a dead pedal/foot rest. The dead pedal is covered by carpet. The pedal locations have been adjusted slightly. The exterior changes include a new rear fascia, new exhaust system, and as well as a new scooped hood. The rear fascia was changed in order to accommodate the new exhaust. The hood scoops have a rubber baffling system to keep water out and let air in. For those who have garage queen GTO’s that do not see the rain (like mine), a popular free mod will be to remove the baffling. All the badges were updated to the 6.0L designation and the rear trunk lid now sports a “Pontiac” script on the driver side. 2004 GTO owners get laid more and are better looking. Other than the above that is about the only differences.

**Semperfiws6** · 12-29-2007, 05:38 PM

Originally Posted by Sarge

The most obvious change is the new LS2 motor that for the most part everyone knows about, same as the 2005 Corvette. Larger bore LS1 based motor with new cam sensor and knock sensor placement. Larger intake and throttle body. Static Compression Ratio is raised and the heads are revised LS6 '243' heads. The 'E40' PCM in the 05 is brand new along with the drive-by-wire throttle body system. The traction control is not as much of a “push back” system anymore. Traction Control is now managed with spark, brakes, and cylinder cutout. I experienced it and it seems to cut more timing then last year. The new PCM is located where the coolant overflow tank resided on the 04. The area between the frame rail and the driver-side exhaust manifold now has much more clearance. The coolant overflow tank is relocated to somewhere below/in front of the air induction box. The ABS system is a new Bosch 8.0 unit with electric brake distribution. The front setup comes from the Corvette style 40.5 mm twin piston calipers and 320 x 32 rotors. The rear calipers were also painted to match but are the same as the 2004 GTO, however the rear rotors receive a slight upgrade from a non-vented rotor to a 286 x 18 vented rotor. The Master Cylinder is an improved 25.4 mm unit along with an improved 8"x9" booster with a dual reaction ratio ("Brake Assist") designed to give a better apply rate above 0.5 to 0.6 g deceleration. The exhaust is very different in 2005 with new manifolds that have less restriction along with a crossover resonator and dual exiting exhaust. The mufflers were said to be less restrictive as well by a small percentage. What was surprising was the fact that the drive train was also upgraded. This does make sense, with the added power output. The pinion gear is stronger, there was a material change and it is shot peened. The CV Joints are from the HSV parts bin from AWD VZ range. The interior remains mostly unchanged. The font in the gauge cluster is more italicized then before, and there was an addition of a dead pedal/foot rest. The dead pedal is covered by carpet. The pedal locations have been adjusted slightly. The exterior changes include a new rear fascia, new exhaust system, and as well as a new scooped hood. The rear fascia was changed in order to accommodate the new exhaust. The hood scoops have a rubber baffling system to keep water out and let air in. For those who have garage queen GTO’s that do not see the rain (like mine), a popular free mod will be to remove the baffling. All the badges were updated to the 6.0L designation and the rear trunk lid now sports a “Pontiac” script on the driver side. 2004 GTO owners get laid more and are better looking. Other than the above that is about the only differences.

that was defenitely some good info. I wasnt expecting something so in depth. I appreciate it. one more question - what CI displacement is the 6.0 liter, is it 366?