High Performance

A crowd begins to gather late afternoon on the second day of the convention in this GMC truck cluster. The attention is not so much on the 1958 GMC stepside 1/2 ton with its Pontiac V-8 plus three factory two barrel Rochester carbs and correct large air filter. The interest is on the contents of the bed.

Here, only heard of by most GMC enthusiasts, is a real inline 302 cubic inch six cylinder engine from the late 1950′s! It has all the aftermarket high performance options of 50 years ago. It sits on a special frame with no body panels obstructing the view. All is there to touch and feel.

The owner is John Christ of San Francisco, CA. He has built this 302 just like it would be for racing in the late 1950′s. John located a new engine about 5 years ago and since has been hunting GMC speed parts so he could build it just like the race track engines of 50 years ago.

This is the first time the 302 has been seen by the general public and almost never had John tried to make it start. He had planned for this moment at the ATHS convention for a long time.

As the crowd grew and watched, the battery beside the engine was connected. The small nearby temporary gas tank was attached to the fuel line. The foot start linkage was pressed by hand and engine began to turn. It does not start and fuel drips from line connections. Yes, John has a good size fire extinguisher.

A water pump drip is not repairable at the show but John climbs into the truck bed with the engine to stop fuel drips at joints and makes several other adjustments. He tries again.

- Howard intake manifold. Allows the use of five Stromberg 97 carburetors. The progressive linkage uses number 2 and 4 carbs when driving normally. Carb. 1, 3, and 5 are waiting to operate when speed is necessary. Fuel economy, are you kidding!

- The bee-hive oil filter beside the block cools the oil as much as it cleans it.

- A 40 year old Wayne valve cover and side plate are almost impossible to find. They  have never been reproduced for the GMC engine.

- The special high volume aluminum oil pan is a necessity when racing on the track.- Fenton headers. These lessen back pressure. Exhaust gases leave the engine much quicker under acceleration.

- A highly modified camshaft is a must! Getting more fuel and air into the combustion chamber adds to the available horse power.

A stock 302 GMC six cylinder with this equipment is why so many small town dirt tracks had to ban vehicles using truck engines in the 1950′s.

The local hobbyist racing a car engine couldn’t win a race against a built up 302. They wouldn’t spend the money to register if a high performance GMC was allowed. To keep the dirt track’s popularity, a sign was often posted “No Truck Engines” but secretly it meant no 302s.