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Thanks to Todd Wenzel of Chevy-Pontiac-GMC (800-321-5515,www.toddwenzelchevy.com) and owner Bruce Corcoran, GMHTP has a badass '05 GTO that has already gone mid-12s on the bottle. We now had our sights on 12s N/A, and these were just the components we needed to get us there. Stainless Works 1.75-inch long tube headers with Random Technology high flow cats (cats will be installed at a later date), K&N FIPK cold air intake, MSD 8.5mm Super Conductor plug wires, Fastchip tuning, short throw shifter from Speed Inc, and Nitto 555R drag radials. |
Since the shifter presented the greatest potential for difficulty, we decided to get that out of the way first. The first step is removing the plastic on the center console around the shifter. This piece starts back by the armrest and the edges can be pried up with a flathead screwdriver... |
...There is only one screw holding the plastic on, located under the storage tray just below the CD player. Once the rubber shelf under the CD player is pulled up, the console lifts right out, but before lifting completely, the controls for the traction control and windows should be unplugged. |
Head technician Junior Perez pulls off the shift knob and accompanying leather shifter boot by pulling straight up, exposing a rubber boot around the shifter handle. There is a brass bracket (not a push clip) holding down the boot, which must be removed or loosened via its bolts, accessible only from underneath the car. |
While the LS2 motor is still relatively new, there are still a handful of bolt-on parts easily installed by any backyard mechanic that can propel a 2005 GTO deep into the 12s. For starters, there is nothing the 364-cube motor likes more than a set of good old-fashioned long tube headers, and while you are at it--why not some tuning? Top that off with a cold air intake, plug wires, drag radials, and a short throw shifter, and you have yourself a manually operated missile.
Stainless Works was well ahead of the game when development was completed on a set of 1.75-inch long tube headers for the 2005 Goat. After making adjustments to the previous year's design (for the '04 Poncho), Stainless Works shipped us a set, which arrived before the end of last summer. A few months later, when we were finished playing around with the nitrous, we headed down to Ron's Custom Auto in Kenilworth, New Jersey, to wrestle the CNC mandrel-bent headers into the GTO's tight engine bay. Having a good pair of hands and a lift would be key for this part of the installation as it unfortunately would require dropping down the steering rack and putting the headers in place from underneath the GTO. The effort, however, is well worth it given the solid construction of the Stainless Works headers. CNC laser-cut 3/8-inch flanges and 16-gauge, 304 stainless steel along with a limited lifetime warranty provide reassurance that exhaust leaks and bent tubing are highly unlikely given the proper installation. Since our Project GTO came with the Corsa chambered mufflers as part of the Sport Appearance Package, we chose to keep the factory catback, but intended to replace the factory cats with high flow units from Random Technology as part of the Stainless Works (emissions legal) kit (PN 05GTOHCAT) that retails for $1,299. Unfortunately, due to some fitment issues, we had to use Stainless Works off-road pipes, which should end up adding a few extra ponies anyway, until the correct pipes to fit the cat are obtained from SW.
The only other challenging feature among the barrage of bolt-ons was the GM Motorsports Ripshift. We obtained this shifter from Speed Inc, GMM's sole U.S. distributor, which costs a very reasonable $299.99 (PN RIPSHIFT). The design of the GTO makes not only for a rubbery and vague shifter feel, but also for difficulty in upgrading to an aftermarket unit. The location of the T56 tranny on the floorpan necessitated a unique shifter location at the very tail of the transmission, and the shifter itself had to be a remote design for an extra couple of inches of clearance. Remote meaning that the shifter linkage is not direct, the shifter handle acts only as a dummy to another lever, which actually does the shifting. The Australian-made Ripshift, though, eliminates the middleman and gives a direct input into the transmission in addition to providing shorter, more precise shifts. Unfortunately, to remove the OEM shifter and install the Ripshift, the tranny would have to be lowered a few inches, making installation without a lift rather difficult. Despite these setbacks, the directions were very clear and Ron's Head Technician Junior Perez knows his way around late model GM cars, so there were no issues.
The last three elements promised to be as easy as you would expect. K&N chipped in one of its Fuel Injection Performance Kits (PN 63-3053), which uses a K&N high performance, open element filter and a slick intake tube. K&N rigorously tests all of its products, so we were sure this baby would be good for a few headache-free ponies and for under $300. MSD was also happy to climb on board as it had just put the wraps on a set of 8.5mm Super Conductor spark plug wires for the LS2 (PN and pricing not yet available). Using a special copper conductor, the wires have less than 50 ohms per foot of resistance, which makes for increased spark efficiency. Since we were already planning to swap out the spark plugs for nitrous friendly NGK TR6s, it required little additional effort. To take advantage of the improvements in efficiency, the factory computer was sent to Fastchip to rid us of the sloppy 11.8:1 air/fuel ratio and the lazy 24 degrees of timing for a mere $450. The coup de grace was a set of Nitto 555R drag radials, measuring 245/45/17 (same as stock), to really give this Goat some teeth. The Nittos are very streetable tires that provide an abundance of traction and cost around $180 apiece.
The best 60-foot time to date was a 2.06 on motor, but with the addition of drag radials and a whole lot more torque, we were hoping to break into the 1.90s. High to mid 12s were also expected, and that was all right with us. Any time you can run 12s with easy bolt-ons that don't sacrifice drivability it is definitely a plus.
There are four 16mm bolts on the tranny crossmember, which are removed with a jack supporting the tranny. A swivel ratchet is used to get around the driveshaft and the tail of the tranny to reach the two 13mm bolts on the shifter boot brackets. | 
Two 10mm bolts connect the shifter handle to the shifter, once it is removed the harness bracket can be unclipped and the rubber dust boot lifts off. | 
Four Torx T27 bolts (on the cover for the shifter) and four Allen head bolts (on the base of the shifter) are all that stand in the way of Junior liberating the stock shifter from the T56 housing... |
...To reach the farthest two Allen head bolts, the tranny had to be lowered another couple of inches and the driveshaft had to be unbolted. | 
The new shifter has an O-ring to form a good seal with the tranny; however, Junior uses RTV to be safe. | 
Four Allen head bolts secure the base of the shifter to the tranny, one of the bolts is shorter than the others--that one goes on the bottom right corner. Two more Allen heads connect the shifter handle to the shifter. |
Before adjusting the setscrews, Junior puts blue Loctite on the threads. The setscrews act as a stop for the shifter, but on regular shifts they should not be making contact with it. | 
The trans is jacked back up, the crossmember reattached, and then the shifter must be clearanced. The floorpan needs to be bent slightly with a pry bar like so to provide 6 mm to 8 mm of clearance from the gold trim ring to the floorpan. Once this is complete, the console, dust boots, and shift knob can be bolted back in place. | 
Moving on to the header installation, Junior unplugs the O2 sensors then removes four 15mm bolts on the crossover and four 13mm bolts on the exhaust manifolds. The two factory intermediate pipes (with the cats) can then be cast aside. |
The driver side on the GTO is cramped quarters, so in order to unbolt the manifolds and install the headers, the steering shaft will need to be unclipped and the rack dropped down. A 13mm socket and a flathead screwdriver are required for the shaft, but the rack requires 19mm and 18mm sockets... | 
...The power steering lines will need to be disconnected as well using a 5/8-inch line wrench on the top and 3/4-inch on the bottom line. The last step is removing the 19mm tie rod bolts, so that the rack can drop completely down and out of the way. Obviously you will be losing some power steering fluid here, so be prepared and pick up a few bottles of the good stuff. | 
After unbolting the BMR strut tower brace and unsnapping the plastic GTO coil covers, Junior removes the dipstick tube with a 15mm socket, then the six 13mm bolts from the manifolds, and off they come. Though GM did beef up the manifolds for '05, they are nothing compared to a good set of long tubes. |