Studebaker
Avanti R3
Engines

The production R3 was a high-performance version of the supercharged R2 engine; the R4 was a high-performance version of the unsupercharged R1 engine. Nine 1964 Avantis with R3 engines were built. Although the R4 engine was optional in 1964, none were produced before the Avanti was discontinued in December 1963. The Granatelli brothers took the first R3, which was an early prototype completed in April 1962, to the Nevada desert where a timed top speed of 171.10 was recorded. For a time, Studebaker could boast of having produced what President Sherwood Egbert proclaimed as "the world's fastest production car." In September 1963, the Granatellis took an R3 to Bonneville where the car did a two-way flying mile at an average of 170.75 mph. Vince Granatelli claims the engines tested on the dyno at 400 gross horsepower, but even a more realistic 300 horses would make this the fastest production Studebaker.

For the R3 Andy Granatelli expanded the standard Studebaker 289 V-8 to 304.5 cubic inches. A Paxton supercharger provided the increased pressure in the fuel-air mixture to achieve greater engine efficiency. R3 and R4 Avantis used a larger rearend housing with heavy duty flanged axles rather than the standard Avanti tapered axle. The rearends were Dana Spicer Model 44's. Specially cast heads with much larger valves were fitted and Iskenderian dual valve springs were optional. A hotter cam was added and heavy-duty bearings installed. Major moving parts were balanced and magna-fluxed. The top edges of the cylinder head bores were chamfered to match the cylinder head combustion chambers, and special flattop forged aluminum pistons filled the holes. Custom exhaust headers were used on all R3's as was a Prestolite transistor ignition system. Chassis and bodies built for R3-powered cars were also modified. Chassis had heavy-duty spring and strengthened control arm bushings. Bodies were shimmed to clear the carburetor pressure box fed by the supercharger.