What Lies Beneath The standard chassis kit is much like the one Walden originally created for his '67. Designed to be a complete drop-in replacement that requires no modification to the car, it comes with rack-and-pinion steering, a complete C4 suspension (front and rear), and a new Dana 44 rearend. Although some components are refurbished, many of the parts are fabricated specifically for the kit, including the halfshafts, "dog bones" (the two camber bars on either side of the rear that replace the trailing arms of the C2/3), and "batwing" diff cover, which is fully CNC-machined from billet to fit the new frame.
One advantage of the C4 setup that's not readily apparent is that it allows you to use deeper offsets-and therefore wider tires-than a stock C3, without flaring the fenders. Wider to the tune of 9-inch wheels up front and 11-inchers in the rear. Although both the front and rear suspensions do follow the late-C4 pattern, the shocks and springs are replaced with coilovers from QA1 as part of the standard package. In fact, the only things omitted from the standard kit are the powertrain, wheels, and brakes.
Engine mounts are available for whatever configuration you intend to use-SBC, BBC, or LSX-and the removable crossmember easily lets you install a variety of transmissions. Of course, since this is a custom shop, you can order these things along with the frame, with a choice of any GM Performance Parts crate engine and a variety of manual and automatic gearboxes.
Similarly, although they don't come standard, you can pick from a dizzying array of brake options that stretch from "standard" Grand Sport C4 calipers to massive six-piston Wilwoods with two-piece rotors. It also bears noting that while Wilwood offers a factory C4 front-brake conversion, the company does not produce one for the rear. Street Shop, however, does. The kit includes a parking brake, and yes, C4 guys, it's available separately.
What Price Performance? The standard package costs around $15,300 fully assembled, or about $7,400 for the bare frame. That sounds a little steep until you start adding up what it would cost to do the job piecemeal. With a rack-and-pinion conversion for a stock C3 running about $1,300, a complete coilover conversion coming in at $2,300 to $2,700, and a five-bar conversion for the rear suspension at $2,700, you're knocking on $7,000 in parts alone. If you want your diff to take the same abuse as the 44, you'll also need to add in a 12-bolt conversion and heavy-duty halfshafts for another $2,600 to $3,200, all of which gets us ominously close to $10,000. Offset trailing arms for wide tires tack on another $400, so once you add in heavy-duty upper A-arms and sway bars, the Street Shop frame is getting pretty competitive with what it would cost to upgrade a stock frame. And even then, the effectiveness of these aftermarket parts will unavoidably be compromised by the inherent weakness of the factory chassis.
Don't think I'm throwing rocks at aftermarket suspension kits. Some brilliant engineering has gone into many of these packages, making it possible to have up-to-date technology applied to a vintage Vette. Besides that, doing it one part at a time is more financially feasible for a lot of folks, because it spreads out the cost over time. Some people simply may not want to do everything to their car, preferring to pick and choose which mods to apply, and what parts to leave stock. For those who want the ultimate, though, the frame package gets you someplace you otherwise can't get from here.