Street Muscle dives head-first into the Pro Touring scene with Project Payback, a 1968 Pontiac GTO built for autocross competition time trials. We’ve partnered with Schwartz Performance and Chevrolet Performance to give the classic muscle car modern performance.
January 12, 2019 – New Year, New Project for Street Muscle: Pro Touring 1968 Pontiac GTO
In August we introduced Project Payback, our 1968 Pontiac GTO – a Pro Touring machine with a downright nasty attitude. If you like A-bodies, Pro Touring and watching tires being spun in anger, this is the project to follow. There is no shortage of autocross events specifically for muscle cars in Southern California, not to mention three excellent road courses within 3.5 hours drive. Ultimately we’d like to see what Project Payback can do on a larger stager at Ultimate Street Car events and the Holley LS Fest.
But, first things first, let’s get to the building. We spent the second of last year planning for the first stage of the build while the initial body work was being completed. We were extremely fortunate that National Parts Depot had everything that we needed to repair the sheet-metal on the quarter panel and fender that had been poorly slathered in body filler prior to purchase. NPD and Best of Show Coachworks have been great partners thus far in the build, and we should be publishing that body work story here soon.
On the mechanical side, we have taken delivery of the entire powertrain. I know there will be purists that say Poncho power is all you need, but we decided to go a different direction on this build. It is true that a stroker kit, valvetrain upgrades, aluminum heads and intake with a quality carb or EFI setup will be make over 700 horsepower naturally aspirated using the factory 400 block. However, our intentions on this build were not to be quite so faithful for nostalgia’s sake. Instead, our goal is to win. We need the sort of reliability that will allow the car to run well on track with minimal changes despite dramatic elevation and atmospheric changes, to drive cross country if needed, and to withstand sustained as well as oscillating lateral g-Forces. For that reason we chose a dry sump Chevrolet Performance LT4 crate engine. And to back it up, we have a Chevrolet Performance T-56 Magnum 6-speed manual transmission and Silver Sport A-body conversion kit.
Not to take anything away from the 650 horsepower powerplant, but the key factor in making the larger A-body hang with some smaller and lighter setups on the autocross course is the chassis and suspension. I put a great deal of research into figuring out what was going to make this car the most competitive, and ultimately it was clear that we needed a whole chassis rather than some bolt-on suspension upgrades. This car had a rough life, so the stock chassis may not be in the best condition (though its measurements did checkout OK). Thankfully Schwartz Performance had us covered. I have been watching their Tempest run for years, so turning to some fellow Pontiac lovers seemed like a natural choice for the GTO. Since second-gen A-bodies come with a 4-ink and coil springs in the rear, the biggest benefits by going with an aftermarket chassis are rigidity and modern steering. Schwartz says its frame is torsionally 200% stiffer and weighs 125 pounds less than the stock chassis. Of course, we will have many other killer parts built into the Schwartz package including massive Baer brakes, Ridetech coilovers, and a Moser full-floating 9-inch. Oh, yes, we’ve come to play.
As I type this, Schwartz is finishing up the chassis to get it assembled and shipped off to PAM’s HQ where we’ll be doing most of the mechanical work on the GTO. Stay tuned for another update when the chassis arrives.