If you are a fan of late-model GM vehicles then no doubt-like me-you have dreamed of burning up the Milford Proving Grounds in one of GM's test vehicles. A location so remote and top secret that it is guarded like Fort Knox, and civilians (like us) aren't permitted to even walk around unsupervised. Matter of fact, I was almost surprised I was able to get my camera equipment back through security on the way out. While there are a few tangible things (that can't be mentioned) lurking around in plain site, the most impressive secrets are just under the surface of the many ordinary looking production vehicles sitting on or driving around the 4,000-acre property. On this particular occasion, though, GMHTP was one of only three media outlets to be given access to the holy land to view and drive the most extraordinary looking vehicles on the premises-GM Performance Parts' collection of hot rods.
Dr. Jamie Meyer of GMPP was very proud to show off several well-constructed platforms in which to showcase its catalogue of LS crate engines, all built in-house. The shop in which GM Performance Division Project Manager Mike Copeland works would be a dream for any builder, with access to any machine or tool you can think of, plus all sorts of CAD and engineering software. However, Mr. Copeland assured us that your typical hot rodder could supplant the E-ROD package-especially in a Tri-Five like the '55 that GMPP lifted from the GM Heritage Center. For those not familiar, the E-ROD package is an emissions-compliant engine (LS3 in this case) that comes with all of the necessary components including a wiring harness, calibrated ECM, exhaust manifolds, catalytic converters, O2 sensors, etc. GMPP expects that possibly by the time you read this the California Air Resource Board (CARB) will have certified the package for use in any vehicle from 1995 or earlier, which of course can be modified by any CARB-approved product for further power increases without losing compliance. Currently the E-ROD comes in four variations: LS3 for automatic transmissions (PN 19244805), LS3 for manual trans (PN 19256487), 5.3L for automatic trans (PN 19256513), and 5.3L for manual trans (PN 19256517). However, GMPP has announced that it fully intends to release a 505-horse LS7 and a 550-horse LSA version.
In a pretty light car, such as GMPP's '55, the 430 horsepower factory LS3 is a potent powerplant-as any Corvette owner can tell you. A great blend of torque off the line and top-end power, which performed flawlessly on Milford's straight. The tall First gear in the GMPP 4L65E trans combined with a set of 4.10 gears, aided by an Eaton posi, stuffed in an S-10's 7.5-inch 10-bolt helps get the two-door off the line in a hurry. This was the least powerful of the group tested, but the most surprising. Saginaw power steering kept the wheel feeling light with larger sway bars, Eaton springs and Monroe shocks all around plus 2-inch drop spindles up front that also gave the impression that this car liked to be thrown around. Of course a set of BFG G-Force T/A tires (235/50R18 front, 245/55R18 rear) also aided substantially in its handling. One of the many trick features designer Dave Ross came up with for the '55, facilitated by Copeland and Jim LaFontaine, was the use of 18x7.5 steel wheels off the (base) 2010 Camaro with custom center caps. The build team moved the centers back 1.250-inches to make it happen, and the rears were widened to 8.5 inches. The large wheels allowed for a set of C4 disc brakes at all four corners to match the LS3's acceleration capabilities.