Low Budget Build: 1947 Chevrolet Autocross Rat Rod

This 1947 Chevrolet truck was built to be an autocross course dominator, and it has won several events already.

But the real story here is that the truck was built, at home by a Father and Son, for well under $2,000 — This was achieved with some good old fashioned thinking and a lot of parts most people would have junked. 

The project was started with the remains of a 1947 Chevrolet 3800 truck.

1947 Chevrolet 3800
The truck was half buried in the ground in a gully on a farm. The owner had a good sized tractor and was able to help us pull it out and force it onto a trailer. The farmer had bought the truck and the title we received was issued in 1960.

The cab was gutted, the gas ax fired up and cutting commenced.

The cab was narrowed nine full inches and three inches were chopped from the top. The cowl and firewall was cut off and narrowed with the original grill, and several more inches of steel were eliminated from the bottom of the cab.

1947 Chevrolet 3800 Autocross Rat Rod Cab
Based off the width of the S-10 frame, my Dad and I decided to cut 9 inches out of the center of the cab so it would fit snug on the frame. When we decided to build a rat rod we wanted an older, narrower cab, but we could not find one in our price range. However, the narrowed cab actually ended up looking somewhat like an older cab. The change was pretty dramatic…

The S-10 frame was cut and welded, shortened to 101 inch wheelbase, and finally boxed end to end. The rear suspension was fabricated using a truck arm style like you’d find under a NASCAR stock car, and the whole things stands on used coil overs sourced from a retired stock car. 

 

1947 Chevrolet Autocross Truck Front Suspension

The front end is a mix of miscellaneous stock car parts coupled with RideTech Strong Arms and coil overs. The front brakes are stock S-10 and modified Camaro Z28 brakes were used in the rear.

The power-plant is a bastard Chevrolet small block 305 that was acquired on a labor trade, and beefed up with some bolt-on go-fast parts and an old school home porting job.

 

1947 Chevrolet Autocross Truck 305 Engine
The firewall/cowl was chopped off, and a smooth smoother firewall was fabricated to maximize clearance. An inset was also added to accommodate the distributor since the engine is set back so far. A bulge was added on the driver’s side to allow for a bit more room for the pedals. Then the floor and a tunnel were fabricated to maximize room. The back part of the floor was eventually covered up as well…

The original build time was about 8 months. Since then on the project has evolved to make the truck faster in order to remain competitive.

The project started with some basic parts:

  • ’47 Chevrolet with clear title – $50
  • ’84 Chevrolet S-10 donor – $200
  • Chevrolet truck bed – $50
  • Cragar Wheels – $300
  • Edelbrock Aluminum Single Plane Intake, Edelbrock Aluminum Water Pump, Circle Track Headers, Circle Track Coil Over Shocks, Steering Wheel & G-Body Posi-Trac Differential – $300 (Swap Meet Bargains)
  • Craigslist Chevrolet S-10 Drop Spindles – $75
  • Glass – $100
  • License – $25
  • Tires – Free (Used some worn out tires donated by a friend to win some free tires at the Goodguy’s Autocross)
  • Headlights & Turn Signals – Free (Bought them with a gift certificate won as a door prize at a car show)
  • 305 Engine – Free (Took it out of a guy’s truck and put in a 350 he had built for it)
  • T5 Transmission & 7.5″ 10 Bolt Rear-end – Free (Came with the S-10)
  • Neon Seats & Seat Belts – Free took them out of a Neon we scrapped for a friend 
  • Most other small parts were either laying around the garage, donated by friends or relatives, or fabricated from scrap – ~$100

’47 Chevy Autocross ~ First Run

’47 Chevy Autocross ~ Coil-over Camera

’47 Chevy Autocross from the Interior

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