This page presents historical information on the Thunder Ranch 904. Visit Rock West Racing for information on the currently available RW GTS kit.

904 Coupe

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Besides it being a good challenge, the decision to replicate the Porsche 904 was a natural progression for us here at Thunder Ranch with our established builds of other historically significant Porsches of the 40’s and 50’s. After completing almost all I could achieve racing my Speedster in the middle 60’s; I thought to graduate from E production by buying 904-093 from Hugh Simpson who sponsored driver Bill Neal. Unfortunately, I only drove the car on the street as I decided I needed to race a much faster car to be recognized and become the professional driver I had always wanted to be. That didn’t work.

904 engine covercarrera script904 webber engine

II must thank two people outside of family, employees, and customers for their help on  this extraordinary car. Heinz Heinrichs worlds’premier 904 expert and coincidently a fellow early 1960’s Hesse Motor Sport Club member in Germany where I worked for GE. Heinz persuaded me to create my 904 not as a normal 4 cylinder car but as an accurate representation of the 904/6‘s Porsche built because nobody was doing it correctly. Brant Parson’s keeper of the Stan Gold’scar collection including 904-006 allowed me access to both 904’s in his shop (904-006 & 904-017) as well as a 910. Without their help and sage guidance our 904/6 replica would not be what it is today. I used my visits to see Mr. Gold’s 910 as inspiration for our chromoly frame design as well as the factory 906 frame drawings I had procured. The goal of our 904/6 replica was to be aesthetically a copy of the original car with chassis and brakes able to handle the power of the most powerful donor 911 motors plus provide a safe environment for the driver and passenger. Since all the cars we will build will be powered by a 911 motor, the T.R. 904/6 was built with all the unique features of 904 six cylinder cars.

904 fuel filler904 rear quarter

Most of the 904/6 changes were subtle and often used on late four cylinder cars or rebodies but some changes were uniquely different. Nonetheless all the six cylinder body changes were made to the T.R. 904/6. From front to rear: the oil cooler opening was larger, the brake ducts larger, and without driving lights, center fill fuel filler, short doors with rocker panels, pull up side windows, “Elephant Ear” large air intakes, center grill area filled, a unique air intake vent was created behind the driver. Like all other T.R. cars and kits the 904 bodies are laid by hand with a blended polyester resin with two layers of matt and a layer of cloth then reinforced with a 1mm or 2mm core material in necessary areas. The body is bonded to the tig welded 1½” diameter/chromoly round tube frame on our 16’ WWII aircraft layout table.

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