When last we spoke of Jeff Hutchens' (Springfield, Missouri) '67 GTO, it was regarding its fuel-injected 1,000-plus-hp twin-turbo 505ci engine in a three-part story that ran in the Oct. '09, Nov. '09, and Jan. '10 issues of HPP. While all that power will snap your neck on launch, it's also important to have a chassis and braking system to rein in those ponies.
To that end, the builder, Muscle Car Restorations in Chippewa Falls, Wisconsin, chose a Schwartz Performance frame as the foundation for a Pro Touring chassis. Based on many years of professional road racing experience, Schwartz sells what is essentially a race car chassis that will bolt to a stock GM A-body. The frame is designed for optimum handling, while maintaining excellent ride quality. Torsional flex is reduced by 200 percent as compared to stock, according to Schwartz, and it's 145 pounds lighter. The frame is also set up for modern suspension, like rack-and-pinion steering and coilovers. Revised suspension geometry provides a negative camber curve and minimizes bumpsteer, and since the Schwartz frame uses off-the-shelf racing parts, Jeff can have whatever level of performance he desires.
Though the outside of the GTO will remain just as Pontiac originally envisioned it, the inside will be fitted with a full rollcage, full rear tubs, three driveshaft loops, and a complete custom floor and firewall. The underneath will be virtually race-ready with a full tubular suspension, QA1 coilovers on all four corners, and four Wilwood six-piston calipers gripping 14x1.25 inch drilled rotors that will turn behind 18x10 and 18x12 inch Weld wheels. Schwartz also supplied race-ready front and rear sway bars. Bringing up the rear will be a full-floating Winters 9-inch. For this installment, we'll cover the frame mods and floor fabrication.
Whether flat out on an open highway or hugging the side of a mountain pass, Jeff should be able to run with and out in front of everything, but his own nerve.
Important things to remember
• Think one or two steps ahead of where you are working now.
• Measure carefully.
• Don't weld it all together until you're done and know that it all fits together perfectly.
• Measure carefully a second time.
• Make difficult parts out of cardboard first to test the design and fit.
• Measure even more carefully a third time.
• Take the time to mock up major components and parts assemblies like seats, heater box, dash, pedals, and so on.
• Check and recheck how everything fits together and then check it again.
• Measure a fourth time if you are not 100 percent sure.
This is the Schwartz double-rail...
This is the Schwartz double-rail frame, which is made from DOM mild-steel tubing. Since the frame is built as a bolt-in replacement for a stock GTO, normally, you would bolt on your chosen suspension, fit your engine and drivetrain, drop on your body, and go racing. For this project, however, it requires modifications given the custom parts MCR is using.
Once the body was positioned...
Once the body was positioned and braced, the entire stock floor and firewall were removed. A dummy block and transmission were also installed. All but the rearmost body mounts needed to be fabricated, as they were removed with the stock floor. The top crossbrace (has "LR" on it) was MIG welded in to stiffen the body shell. Note the body is solidly mounted to the frame with metal spacers used for proper positioning.
MCR decided that an 1/8-inch...
MCR decided that an 1/8-inch mild steel mid-plate engine/trans mount would be a good idea to help keep all the horsepower aimed in the right direction. A simple tab welded to the frame provides a bolt-on mounting point.