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What Is The Best Supercharger Combination For A Small Block Chevrolet?

Author: Richard Holdener | 12/28/2020 < Back to Motor Life Home
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When it comes to supercharged power production, what is the better choice, a bigger motor with a small blower, or a smaller motor with a bigger blower? In truth, the best combination for maximum power is a bigger motor with a bigger blower, and we are going to cover that option as well, but people select supercharged combinations for different reasons. Heck, for some, they just want the sound and visual statement. Others are just looking to add a little something to their already potent combination. The final group wants everything...all the power, all the glory and all the noise of a big, nasty blower sticking out of the hood. For these guys, the only thing better than a little blower is a big blower. The only thing better than 5 psi is obviously 10 psi. More, more and much more is the only order of the day they know, but before we take a look at the ultimate answer we need to look at the other supercharger setups. To illustrate the differences in blower combinations, we ran no less than three different supercharged small blocks.

We ran each engine naturally aspirated for a baseline test. This is the 383 stroker that we used for our Weiand 177 test. It's a 10:1 engine with CNC-ported AFR heads and a stout camshaft. With MSD ignition and a Holley 950 CFM carburetor feeding it, the 383 laid down 550 horsepower and 491 ft/lb of torque...very respectable!


Test mule number 1 was the bigger motor/smaller blower combo, with a 383 stroker Chevy topped by a Weiand 177. Why would someone want this combination? Well, what if you already had a nice 383 Chevy, ready to go? If you had a 383 stroker, especially a healthy one, and wanted just a touch more power...you know, just in case...then a supercharger would be a simple step towards the right direction. Maybe you just want that 383 to look a little more menacing, or make just a little more noise, or you simply just want to say that you have a supercharged small block. Whatever the reason, the 177 blower has a lot to offer, both in terms of performance and as a visual statement, especially when polished. The 383 test mule was no slouch, even before the blower, with 10.0:1 compression, AFR 210 heads and a thumping ( .600 lift, 252/256, 108 LSA) cam. Run naturally aspirated, the 383 produced 550.2 horsepower and 491 lb-ft of torque. After installation of the Weiand 177 and single 950 CFM carburetor, the supercharged combination thumped out 645 horsepower at just 6 psi. This blower would be best applied to a smaller, less powerful 350, but who doesn’t want an extra 100 horsepower?


Test motor number two was the polar opposite of test motor number 1. By that, we mean it combined a smaller motor and a bigger blower. For most supercharged combinations, the blower determines the eventual power output, but in this case, the test motor was actually the deciding factor. This supercharged 350 started out life as a simple GM crate motor, a 195 horsepower crate engine. In truth, the 195 horsepower rated GM crate combo actually made closer to 270 horsepower once we added a dual-plane intake, Holley 650 CFM carburetor and set of long-tube headers, but it was hardly the most powerful tool in the shed. Though blessed with a 4-bolt block, the 8.5;1 compression, sub .400-lift (194/202 duration and 112 LSA) cam and small-valve heads combined to produce what can best be described as little more than a simple replacement truck motor. It’s not the romping, stomping, rev-happy small block that everyone wants, but that doesn’t mean you can’t successfully add boost to it. Run naturally aspirated, the basic small block produced 271 horsepower and 351 lb/ft of torque. After adding the hefty (and impressive) 6-71 blower with twin Holley blower carburetors, the power output skyrocketed to 389 horsepower and 441 lb-ft of torque (at 10.6 psi). Think of this more as a deceptive small block than an actual performance build up...something that provides the look and feel of a wicked blower build, but all the drivability of a stock small block.


It is difficult to guess how many people would go for the first two versions, but many make the immediate jump to the full-fat build. The key to making power is to combine a big (powerful) motor with a big (powerful) blower. The final build up included just that, as we combined a 400-inch stroker small block with a Weiand 8-71 blower. The combination of a healthy small block, even more powerful than the 383 used in the first combination, being force-fed by a big blower resulted in some serious power. How much horsepower, you ask? Well, using Dart Pro 1 CNC-milled heads, a healthy cam (.671/.660 lift, a 250/260-degree duration split and 116-degree LSA) and single-plane Dart intake, the stroker produced 565 horsepower and 489 lb-ft of torque naturally aspirated, nothing to sneeze at. After installation of the Weiand 8-71 supercharger, the boosted power output jumped to 819 horsepower and 667 lb-ft of torque. The Weiand 8-71 perched on top of the 400-inch small block was sporting a pair of Holley 750 blower carbs, and supplied a peak boost reading of 11.7 psi.


You can have your cake and eat it too. You can build a mild engine that has the look and intimidation factor of a big blower machine yet use it everyday, if you desire. Or you can go straight for the kill, with tire-liquefying power on command and a blower whine that’ll raise the dead. The choice is up to you, but as you can see, the answer is always the same: "supercharge it."


SBC 383 dyno run with Weiand 177

We knew our 383 was healthy, so adding the Weiand 177 supercharger was only going to make things fun. Power jumped up nearly 100 horsepower, to 645 horsepower and 565 ft/lb of torque with only 6 psi of boost going into the engine.

Crate 350 with 6-71 blower dyno test

Our first test was a happy medium. The next test was a combination of too much blower and not enough engine. This crate 350 only pushed out 271 horsepower and 351 ft/lb of torque on the dyno...and was only rated for 195 horsepower! This isn't an ideal candidate for a 6-71 and dual 750 CFM carburetors, but the mild Mouse produced 389 horsepower and 441 ft/lb of torque.

400ci small block with 8-71 blower dyno test

The last setup was mild. This was the wild form: a 400ci unit with CNC-ported Dart Pro heads and a wicked solid-roller camshaft. Naturally aspirated, the big boy thumped out 565 horsepower and 489 ft/lb of torque, in the neighborhood of our 177-blown 383ci unit. But with the 8-71 topping the engine, the 400 took the crown: 819 horsepower, 667 ft/lb of torque.

Blower Test 177 Graph

In truth, we were a little disappointed when we first ran the 177 supercharger on the healthy 383 stroker. The reason was that the blower only improved the power output by 50 hp, from 550 hp to 600 hp, but after installation of a larger crank pulley to increase the blower speed, we were rewarded with additional boost (up to 6 psi) and power. After the pulley upgrade, the power output jumped to 645 hp and 565 lb-ft of torque.


400ci SBC dyno graph

On the opposite end of the spectrum, our big-and-bigger setup certainly had the beef to back up the looks. The 400-inch stroker was plenty healthy in NA trim, thanks to solid-roller, CNC-ported Dart Pro 1 heads and single-plane, Dart intake. Even before the boost, the 400 pumped out 575 horsepower and 489 lb-ft of torque, but after adding boost from the 8-71, these numbers jumped to 819 horsepower and 667 lb-ft of torque at 11.7 psi.


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