Swiss Cheese Pontiacs: Drilling Detroit Full of Holes

Detroit Had Discovered Weight

The other factories were reaching the same conclusion. Chevrolet was building lightweight Impalas, Ford was learning how much perfectly good automobile could be removed from a Galaxie, and Chrysler was combining aluminum pieces with Max Wedges.

Pontiac had already used aluminum body parts on its Super Duty Catalinas. That helped, but the 1963 Catalina was still sitting on a full-size frame containing a heroic amount of steel.

Most automobile engineers would look at a frame and see the structure holding the car together. Pontiac Engineering looked at the same frame and saw inventory.

They Started With the Frame

A normal boxed frame rail is strong because it is a box: top, bottom and two sides tied together to support an automobile through years of potholes, railroad crossings and owners who never once wonder what is happening underneath them.

Pontiac’s drag racers were not terribly interested in the next ten years. They were interested in the next twelve seconds.

Sections of the frame boxing were removed, and then the engineers began punching holes through what remained. Not a couple of tasteful little holes either. Roughly 120 went into the frame rails until the chassis looked less like something from General Motors and more like a steel beam that had lost an argument with a drill press.

The nickname took care of itself: Swiss Cheese.

A Hole Weighs Almost Nothing

That was the beauty of the idea. One hole saves very little weight, which gives a sensible person no reason to get excited. Drill another hundred or so and suddenly a respectable pile of Pontiac is lying on the shop floor.

The bottom portions of the boxed rails were removed in places, leaving weaker U-shaped sections and forcing the body to help carry loads the frame had once handled by itself. This would have been a rotten idea for a Catalina expected to spend a decade crossing railroad tracks.

Fortunately, Pontiac was not building these things for traveling salesmen.

Then the Rest of the Car Became Suspicious

The drill press had done its share, but Pontiac was nowhere near finished. Steel body pieces gave way to aluminum in the hood, front fenders, inner fenders, radiator support, bumpers and brackets. Anything heavy enough to show up on a scale was now entitled to a nervous glance from the racing department.

The front sway bar disappeared because nobody bought a Swiss Cheese Catalina for its graceful cornering manners. Sound deadener and body sealer went away for the same reason, while the battery moved to the trunk where it could help weight distribution instead of merely occupying its traditional address.

Pontiac had begun with a perfectly respectable full-size car and was systematically removing the respectability.

Even the Drivetrain Went on a Diet

The attack on weight continued underneath. Aluminum showed up in bellhousings, exhaust manifolds and even rear axle center sections because making ordinary parts lighter was no longer enough. Pontiac wanted parts that made experienced mechanics stop, stare and ask whether anybody had considered what happened after the quarter-mile was over.

Aluminum exhaust manifolds were a fine example. They saved weight and did their job, provided nobody became overly sentimental about long-term durability or subjected them to more heat than they cared to tolerate.

A street car needed parts that survived years. A factory drag car needed them to survive the race.

Fortunately, They Kept the 421

Under the aluminum hood sat the reason this exercise made sense in the first place. Pontiac’s 421 Super Duty received serious compression, improved cylinder heads, more camshaft and dual Carter four-barrels sitting on the famous bathtub-style intake.

Pontiac officially rated the strongest version at 410 horsepower. Factory racing programs of the period were remarkably modest whenever horsepower figures might find their way onto official paperwork.

Whatever the engine actually produced, it was plenty, especially after Pontiac had spent so much effort making sure the 421 did not have to drag every piece of the original Catalina along with it.

There Were Fourteen

Pontiac did not build Swiss Cheese Catalinas by the thousands, hundreds or even dozens. Fourteen were produced and sent where they could do some useful advertising: established Pontiac racers and factory-backed operations around the country.

Mickey Thompson received two of them. That tells you about all you need to know concerning Pontiac’s intended customer base. Nobody in the sales department was expecting a run on Swiss Cheese Catalinas from accountants looking for dependable transportation.

Fourteen cars were enough to make them factory-built machinery. Not enough to clutter the employee parking lot, but enough to make the paperwork useful.

The Rulebook Had Helped Create the Thing

This was one of the better tricks in early factory racing. The rules tried to keep competition connected to recognizable production automobiles, so Detroit began producing increasingly specialized automobiles specifically to satisfy the rules.

Need factory parts? Pontiac would manufacture them. Need a production frame? Pontiac would start with one, then remove a surprising percentage of the pieces that made it such a splendid production frame.

The engineers had not replaced the chassis with a purpose-built tube structure. They had merely attacked the original one until daylight became one of its more noticeable features.

Still a Pontiac. Just considerably more ventilated.

There Was One Small Problem

Automobile engineers generally put metal into a frame because they have some reason for wanting it there. Pontiac eventually rediscovered this old engineering custom.

The Swiss Cheese cars were light and fast, but the weakened frames were also flexible. Cracks developed and repairs became necessary around areas taking serious suspension loads, which should not have surprised anybody after removing portions of a boxed frame and punching more than a hundred holes through what remained.

Eventually the structure developed opinions of its own. That would have been unacceptable in the family Catalina; in a factory drag car, it was maintenance.

And the Ridiculous Thing Worked

All the drilling and aluminum would have been nothing more than an interesting way to ruin a perfectly good Pontiac if the cars had been slow. They were not.

The Packer Pontiac Swiss Cheese Catalina driven by Howard Maselles ran 12.27 seconds at more than 114 mph and established an NHRA class record. A full-size Pontiac was running deep into the twelves in 1963 after engineers had attacked its frame with the sort of enthusiasm normally reserved for demolition work.

Suddenly the holes looked a lot less silly.

Pontiac had demonstrated one of racing’s simpler truths: horsepower never has to accelerate weight that is lying on the shop floor.

Then GM Pulled the Plug

The timing was lousy. Pontiac had spent years becoming one of Detroit’s most aggressive racing divisions, the 421 Super Duty program was mature, the Swiss Cheese Catalina had pushed weight reduction to a ridiculous extreme, and even more radical Super Duty Tempests were coming.

Then General Motors ordered its divisions out of organized factory racing.

The official pipeline shut down, leaving just fourteen Swiss Cheese Catalinas behind as evidence of what Pontiac engineers had been doing before somebody upstairs decided everybody needed to behave themselves.

That probably saved quite a few drill bits.

Less Pontiac Was the Answer

Pontiac never had to make the Catalina smaller. It simply removed the pieces it could live without, replaced steel with aluminum and drilled holes through the pieces it still needed.

When the engineers finished, the car still looked like a full-size Pontiac from across the parking lot. Underneath, it was a 421 Super Duty surrounded by just enough Catalina to keep the paperwork interesting.

Most manufacturers spend a great deal of effort keeping holes out of a new automobile. Pontiac built fourteen special cars and made the holes factory equipment.

Less car cost more money, went faster and left enough metal on the shop floor to explain exactly where the performance came from.