The 449ci Pontiac V-8 used...
The 449ci Pontiac V-8 used in the Penfound Design Sabertooth '64 GTO is actually based on the Goat's original 389. The traditional Tri-Power Pontiac V-8 combination retains the GTO's mystique, but is updated and refined formodern performance levels. Here, it's installed on the Weber Racing Equipment dyno rig.
Last month, the '64 389 planned for installation in the Penfound Design Sabertooth '64 GTO Pro Touring project car was dropped off at Weber Racing in North Ridgeville, Ohio. Collectively, Bryan and his dad, Dave Weber, have a tremendous amount of experience with Pontiac V-8s, so Bryan was quickly able to formulate a plan to achieve Barry's performance objectives.
As mentioned, Barry Penfound's intention was to create a Pro Touring GTO that was a more stripped-down, performance-oriented machine than many of the genre. It wouldn't have air conditioning or other add-ons that would increase weight and decrease performance.
It was also important to Barry that Sabertooth remain true to the original GTO image. For him, that meant a traditional Pontiac V-8 and three two-barrel carbs. Fortunately, the GTO's original 389 was still in the car, so it was used as the basis for the engine buildup.
While at Weber Racing, it became a 449ci, Edelbrock-headed beast that was topped off with one of the Barry Grant SixShooter setups, which offers a modern approach to the Tri-Power systems we are now so familiar with.
The carbs used on the SixShooter...
The carbs used on the SixShooter system are two-barrels closely related to the Demon four-barrels marketed by Barry Grant. They use the same jets, air bleeds, and fuel bowls, and share some gaskets. Rated at 250 cfm per carb, they are well-sized for a street/strip Pontiac V-8. The intake is a new design that offers lighter weight and increased performance over the stock cast-iron Tri-Power unit. Like the original Tri-Powers, the center carb serves as the primary carburetor, while the outboard carburetors use a progressive throttle linkage connected to the center carburetor--no synchronization is needed.
The end result was an engine that was substantially larger in cubic inches and more powerful and lighter than the original 389, all positive attributes to have in a performance-oriented Pro-Touring machine.
Time For The Dyno
You may believe that in the world of car magazines, everything works without a hitch the first time around, and everyone involved high-fives each other to celebrate yet another perfectly executed victory to present to our readers--right? Not quite.
Contrary to popular belief, the car magazine world is the same one we all live in and, of course, snags do occur--and as ol' Murphy said, ". . . and at the worst possible time."
The SixShooter system used was one of the first production models sold (Barry Penfound waited months to get it) and, truth be told, there were bugs to work out. There were some alignment issues with the carbs, as the bolt holes were not in the right locations and the throttle blades didn't line up correctly. Fortunately, Bryan was able to fix those problems without too much trouble. "We found that the first 50 Pontiac SixShooter systems that were sold had this problem," said BG technician Jeff Edwards. "We quickly corrected the problem and haven't seen it return." According to Penfound's receipts, the ship date of this particular system was March 28, 2007, confirming it was one from that first batch.
The center carburetor is equipped...
The center carburetor is equipped with an electric choke, easing the warm-up operation.
Once installed on Weber Racing's new Land and Sea dynamometer, the 449 started up and ran, but wouldn't rev past 4,000 rpm. After finishing a few shakedown pulls, fuel shot out of the rear carburetor. Going right into troubleshooting mode, the carbs came off and the fuel bowls were opened up. "We were surprised to find that the carbs were all full of metal shavings," said Bryan. "It looked like silver metallic paint. The fuel level was also altered, which caused the bogging problem."
After the shavings were cleaned out of the carburetor, the problem persisted--the engine still wouldn't rev over 4,000 rpm. The carbs were once again removed and cleaned out, but more shavings showed up in the fuel log. Fortunately, the shavings stayed in the carbs and didn't reach the engine, but they did cause a premature end to the dyno session.
The SixShooter system was returned to Barry Grant and to its credit, the company stood behind its product, refurbished it, and sent it back.
"We are aware of the metal shavings issue and have instituted a different wash process, which has solved the problem," said Edwards. "While there may be some older units sitting on shelves that still have them, if you order the system from a high-volume outlet like Jegs, there won't be a problem."