Originally Posted by RoHo

What is the 500 HP package?, been thinking about a Head and Cam package myself

Originally Posted by Beaver06

I am thinking of taking my 04 Z to 21st CMC for the 500hp H/C package. Just wondering what the rest of you think in regards to this mod, (pros and cons). Thanks in advance for any comments/advice.

Originally Posted by RoHo

How fast is it and did you pick up the additional 100 HP?

Originally Posted by roushraven

I made it back from 21st Century Muscle Cars thankfully safe and in one piece.

Following are my initial impressions after nearly 1500 miles of break-in and some pictures. The mileage comes from driving 500miles in and around Dallas and N. Dallas, the 700 mile road trip home and another ~150 miles around Omaha.

Impressions

21st Century Muscle Cars is a AAA class operation and here's another big thank you to John, Andy, Patrick and Jonathan for the excellent work and kindness. My heads and cam package includes:
LPE heads, GT12 with 112lsa (not sure if I can publish the specs), underdrive pulley, LPE throttle body, LPE oil pump, Hurricane CAI, Halltech air bridge, 30lb SVO injectors, Beru plugs, Magnecor wires, radiator screen, Elite Engineering tunnel plate, LPE hardened output shaft, Textralia OZ700 clutch, Baer eradispeeds, Motorsport wheels, LPE fuel rail cover and floor mats, and finally poly sway bar bushings. In 125 degree heat and with 91 octane in the tank (no other additives) the car made an unprecedented 450 rwhp and 390 rwtq.

I'll post a sound clip in a later post but I think it can best be described as deep, mellow but lopy; especially after the pcm goes in closed loop. You definitely feel and see the shake, I like it - a lot. Inside the car, the exhaust tone seems smoother and "quieter" than before. I can't explain why, but it is what it is. Outside the car it sounds sweet especially under WOT. Not harsh at all. Acceleration is smooth, although you definitely can tell where in the curve the cam comes on. It really begins to pull from 3000rpm. The car cruises well at 13-1500 rpm in all gears; but "lugging" is felt below 1300rpm unless under acceleration.

As for acceleration, my perception is that the car pulled harder before the changes from off-idle or from cruise until about 3000. I attribute this to the steel flywheel vs aluminum and the heavier Motorsport wheels. Those two things and the cam have made getting used to starts from a stop especially tricky. The clutch itself is great and the pedal feel is just like stock. I'll try my OEM wheels before I make my final judgment but at my torque level it may not have been the best choice given the heavier flywheel. (Update on edit: My perception above was colored by the effect of extreme air temps and engine heat soak during that period 95-100 degrees. Now that I have driven it up where the average air temps were mid 80's -peak- the car accelerates very hard and noticeably harder than before - in all gears. The clutch operation is fine. As for the Motorsport wheels, all I can say if the car pulls like this with them then it will be scary with stock weight wheels. )
The most noticeable improvement other than the power was the addition of the tunnel plate and poly bushings. The car has a significantly more solid feel to it than before. All aspects of cornering have become more controlled with the new bushings though there is a small compromise - I can sometimes hear them squeak. The combination of baer eradispeeds and Z06 pads is awesome albeit with increased dust. I was using the ceramics but the trade-off in increased stopping power is worth the extra dust.

I did have to get used to the car (cam and new clutch) and I think I now have it handled. In cool temps the car is scary fast but controllable and I though I love the top end; I would prefer more low end grunt.


-RR

Originally Posted by Beaver06

SOunds pretty good, RR. Thanks for the input. I guess I have to make an appointment then go for the 1400 mile round trip.