350 Chevy Small Block V8, Supercharger and Turbocharger

Motorheads, rejoice! Roots blowers have always been cool! In recent years, many thought the roots type blower was D.O.A. Comment sections of engine builder websites read like eulogies: “Roots blowers are so 90s” and “It’s time to get with the new technology.” Even though new performance engines were thought to be leaving roots blowers in the past, they really never left the arena of street rods, muscle cars, race cars and even new cars.

The SBC supercharger offers huge horsepower increases,  and to be honest, there still is no other performance bolt-on for your small block Chevy that looks more impressive than a SBC supercharger in the form of a 6-71 or 8-71 roots type blower kit. A SBC supercharger lets others know that your engine makes horsepower. If it doesn’t, you’ve probably crossed about 4 spark plug wires because when a SBC supercharger kit is installed, big horsepower is just a given result. If you doubt what’s being said here, just ask guys like Don Garlits or Ohio George Montgomery how important the Jimmy Blower has been for racing and rodding.

The roots type supercharger, or “blower” has a long history in American Industry. Way back in 1860, Philander and Marion Roots developed the first roots type blower for use in blast furnaces. From there, the design, with it’s simple two or three lobe rotors found their way into all sorts of applications in which the air had to be moved from one place to another. In 1938, General Motors developed the famous Detroit 2 stroke diesel engine. These engines, by their design, had no way to get rid of, or “scavenge” the exhaust, so the roots blower was utilized. The blower’s purpose was to “blow” the exhaust out of the cylinder after the power stroke. Some of the common Detroit Diesel engines that used these roots blowers displaced 71 cubic inches per cylinder. So, if it was a 6 cylinder, it was called a 6-71, if it was a smaller 4 cylinder, a 4-71 and of course if it were an 8 cylinder, it was an 8-71. We’ve all heard the term “6-71 Jimmy Blower”. Well, once you know that the term Jimmy was slang for GMC, you know how the term “6-71 Jimmy Blower” was derived.

A roots supercharger is one of the most effective-power adders of all time in muscle car, marine racing, tractor pulling and drag racing engines. It didn’t take hotrodders of the 1950s very long to figure out how to bolt a modified 6-71 GMC supercharger onto their small block Chevy. The 350 small block supercharger race engine was born. With the ability to easily double the engine’s output,  it was just a matter of time before they started showing up on street engines. By the time the 1970’s rolled around, you really didn’t have an ultimate powerplant unless it had a 6-71 or 8-71 supercharger on it. Once the 350 Chevy became America’s apple pie engine, a Chevy 350 supercharger was the ala-mode to go on top.

A roots type supercharger has one advantage over other styles of superchargers. They make strong boost at lower RPMs, and this makes them a natural for both street use and drag racing. Centrifugal superchargers usually have to “spool up” a bit like a turbo before they make substantial boost but the roots blower has it from the get-go. One of the other great benefits of a SBC blower equipped hot rod, is the phenomenal sound the supercharger puts out. That unique blower “whine” is unmistakable when heard.

Roots blowers, the kind we still use on hot rods today, are known as positive displacement air pumps. With each rotation of the rotors, it moves air from the top to below where the air “piles up” and creates positive pressure or “boost”. This boost builds positive pressure, forcing more air and fuel into the combustion chamber and makes your SBC supercharger equipped engine think it’s twice its size.

If you want the ultimate in appearance for your small block Chevy, a SBC supercharger kit is the only way to go. A SBC supercharger kit from Speedway Motors is one of the  most cost effective and reliable ways to increase horsepower and torque. Speedway Motors offers a full line-up of Weiand supercharger kits. If you want a single four barrel, low profile “sleeper” type supercharger kit, the Weiand #7740-1 144 size is a no-brainer. If you want that large-and-in charge power of a Weiand 6-71 for dual quads,  look no further than #4257582P. It’s not uncommon to get more than 600 or even more horsepower from a Chevy 350 supercharger kit, and you also get rock solid reliability with tire shredding low end torque. Hey, when you have a SBC blower equipped car, and dual quads poking out the hood with all that gleaming polished aluminum, you just might be the king of the road.