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How to Build a Budget 637hp 385ci Small-Block Engine

Budget-Based, Blown & Bad! - Building a 637hp small-block on 91-octane

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This past decade sure has been full of amazing advancements in automotive technology. If you recall, anyone with a 500hp engine was pretty much king of the street. These days, you better be packing a lot more heat to try and take that crown. A positive side effect of all these advancements, it's also allowed for more enthusiasts to get into the 500hp realm with relative ease—and without depleting the bank.

Case in point, our latest 385ci small-block build was done rather conservatively, but we wanted to see just how far we could take a budget-based build with a supercharger for the street. That meant keeping driveability in the equation, and a thirst for today's petrol. Of course, superchargers and budget-based combos may seem at odds, but we think you'll be pleasantly surprised at just how affordable it can be.

For this build, we saved an old 350ci small-block from becoming a boat anchor and took it over to A.R.E. Performance & Machine in Simi Valley, California. Once there, owner and lead engine builder, Rocco Acerrio, sonic-checked the block to make sure it was up to the task.

With a clean bill of health, we went straight to Speedway Motors' website and started to piece together a 9:1-compression 385ci short-block. This included everything from the rotating assembly and gaskets to the oil pan. For the top end, we reached out to Brodix for its IK 200 cylinder heads. We've heard great things about these lightweight lungs, so this was the perfect opportunity to try them out. At just $1,300, they come complete with stainless 2.02/1.600-inch intake/exhaust valves and double springs. Topping off the combination is a TorqStorm supercharger fed by Demon Fuel System's latest Mighty Demon 650-cfm blow-through carburetor.


TorqStorm is a new player in the supercharger world, and one you're going to start hearing a lot more about. For $2,800, you get a high-quality unit built out of billet aluminum. TorqStorm also offers complete systems for LS, small-block, and big-block applications. For late-model truck guys, TorqStorm even has a setup for Silverados. And when we say complete, that's no joke; these include everything you need for a simple installation. Each system comes with all the necessary brackets, a carburetor hat, the pulley assembly, the belt, a blow-off valve, and hardware. You also get your choice of a natural or black finish; you can also opt for the polished finish for an additional $500. As an added benefit, TorqStorm is also offering a limited life time warranty if anything happens (workmanship or mechanical failure), TorqStorm will repair the supercharger head unit free of charge.

350ci Small Block Install Arp Main 2/36

You’re only as strong as your bottom-end prep. Since we were planning to pump up this gem up with 10 psi of boosted goodness, we added ARP main studs to help eliminate any potential main cap movement.

350ci Small Block King Hp 3/36

We also used a set of King HP small-block bearings; you want quality bearings to endure the added horsepower levels.

385ci Small Block Scat 4/36

For the rotating assembly, Speedway Motors sent us a 4340 forged Scat crankshaft. Combined with the 4.040-inch bore and 3.75-inch stroke, this transformed our old-school 350ci to a more potent 385ci.

385ci Small Block Position Main 5/36

With the crankshaft laid in place, lead man Rocco Acerrio from A.R.E. Performance & Machine positioned the main caps and applied a dab of ARP Ultra-Torque. We use this assembly lube on each of our builds; you can expect to get within 5 percent of the required preload on the first pull of the torque wrench. More importantly, it’ll stay consistent with each cycle prep during pre- and final assembly.

385ci Small Block Torque Arp Main 6/36

With the crank and main caps in place, each ARP main studs were torque to 80 ft-lb. Our crank endplay checked in at 0.006 inch, and we were able to rotate the crankshaft easily by hand.

Speedway Motors I Beam 7/36

For rods, Speedway Motors supplied us with Scat 4340 forged I-beam rods with ARP cap bolts.

Arp Cap 8/36
Speedway Motors 9/36

The pistons, also from Speedway Motors, are 9:1 slugs with a slight dish and dual valve reliefs.

Speedway Motors Oil 10/36

To keep the oil supply fresh, we used a high-volume oil pump, again from Speedway Motors.

Speedway Motors Rings Set 11/36

Using the Speedway Motors’ supplied rings, the top and second rings are 1/16-inch thick with a 3/16-inch-thick oil ring. Gaps were set at 0.018 for the top and 0.024 for the second ring.

Arp Ring 12/36

With the piston and rod assembled, Rocco used an ARP ring compressor and gently tapped them into the cylinder bore.

385ci Small Block Torque Rod 13/36

Rotating the 385ci, the rod bolts were then torque to 45 ft-lb.

385ci Small Block Install Comp Cams Hydraulic Roller 14/36

At center stage is a COMP Cams hydraulic-roller camshaft. This is a XFI (Extreme Fuel Injection) cam with 230/236 degrees duration at 0.050 and 0.576/0.570-inch lift with 1.6:1 ratio roller rockers. Even though we’re running a carbureted blow-through setup, we chose the XFI cam because we wanted an off-the-shelf item and a wider lobe separation, which made it better suited for the blower.

385ci Small Block Cloyes Double Roller 15/36

To keep the timing in check, we used a Cloyes double-roller assembly from Speedway Motors.

385ci Small Block Cylinder 16/36

Our cylinder head of choice is a complete set of Brodix IK 200s. These feature a 200cc intake runner and come with 2.02/1.600-inch intake/exhaust valves.

385ci Small Block Exhaust 17/36

The Goods

Part Numbers

A.R.E. Performance & Machine
Machining & assembly Call
Brodix, Inc.
IK 200 cylinder heads 1021007
IK 200 manifold HV 1016
Comp Cams
Camshaft 12-467-8
Roller rocker 19002-16
Lifters 853-16
Pushrods 7956-16
Demon Fuel Systems
650-cfm Mighty Demon, Blow-through 5282020BT
Performance Distributors
D.U.I Distributor 12720
Melonized gear 78068
Livewires C9051
Battery and tach connectors 111111
Speedway Motors
Forged SBC rotating assembly 9151234
King HP rod bearings 910-807HP-STD
King HP main bearings 910-557HP-STD
Push-in valve cover breather kit 54568810
ARP Fasteners, SBC head bolts 1011343601
ARP Fasteners, SBC kit 1015349501
ARP Fasteners, SBC main studs 101RMS2
Oil pan, '55-79 9109005
Pioneer brass freeze plug set 577PE100BR
Dipstick 7204957
Labor to side clearance rods 91510200
Labor to balance rotating assembly 91510200
Supercharger kit SBC

385ci Small Block Torque Cylinder 18/36

With the head gaskets positioned, the cylinder heads were torque to 80 ft-lb.

Comp Cams High Energy 19/36

For the lifters, we used a set of COMP Cams High Energy hydraulic-roller lifters, a retro-fit setup for non-roller blocks. Be sure to double-check your block and personal parts list to match the appropriate lifter for your application.

385ci Small Block Lifters 20/36

For the lifters, we used a set of COMP Cams High Energy hydraulic-roller lifters, a retro-fit setup for non-roller blocks. Be sure to double-check your block and personal parts list to match the appropriate lifter for your application.

Comp Cams 21/36

We also used a set of COMP Cams 5/16-inch, 0.080-wall pushrods with a 7.450-inch length.

385ci Small Block Pushrods 22/36
385ci Small Block Comp Cams Roller 23/36

To complete the top end, we complemented the Brodix heads with COMP Cams Ultra Gold 1.6:1 aluminum roller rockers with 3/8-inch studs. Lastly, we mounted the Speedway Motors’ fabricated aluminum valve covers.

385ci Small Block Speedway Motors Steel 24/36

To seal the bottom end, we used a Speedway Motors’ steel stock small-block pan. This was a bargain at $30, with perfect fitment, and it fits most ’55-79 applications.

Torqstorm Supercharger 25/36

Installing the TorqStorm supercharger was ridiculously easy. And because the system features a self-contained oil supply, this eliminates the need for any additional oil lines.

385ci Small Block Mount Blower 26/36

We started by mounting the blower brackets; there are only four bolts to secure the brackets and it mounts directly onto the cylinder head. We should also note that TorqStorm offers a lot of options, including your choice of driver- or passenger-side-mounted supercharger systems. Ultimately, the choice is yours and you should go with whichever system will adapt the easiest to your specific combination.

385ci Small Block Secure Front 27/36

Next, the front-plate that actually holds the blower was then secured to the base bracket with four billet spacers.

385ci Small Block Bolt Torqstorm 28/36

Once the brackets were in place, we bolted the supercharger onto the front plate.

385ci Small Block Mount Timing 29/36

We then mounted the Speedway Motors timing cover and balancer, and the TorqStorm billet aluminum lower blower pulley.

385ci Small Block Finished Blower 30/36

Here’s a good look at the finished blower assembly. We used the supplied Goodyear 8-rib serpentine belt and snugged the belt with the tensioner.

385ci Small Block Air Filter 31/36

One of the qualities we like about the TorqStorm setup is that it comes complete with everything you need for the installation. The back of the blower also offers an adjustable scroll, which allows you to ideally position the discharge tube to your carburetor. And yes, even the air filter assembly is included.

385ci Small Block Discharge Tube 32/36

This system really impressed us. It’s the first blow-through kit we’ve used that supplies you with a complete discharge tube assembly with the blow-off valve, V-band clamps, air filter, and a carburetor hat. That means you don’t have to spend time fabricating or farming it out to a qualified welder.

Mighty Demon Blow Through 33/36

Our carburetor for this build is Demon’s latest Mighty Demon blow-through carburetors. We used a 650-cfm carb; however, Demon also offers optional 750- and 850-cfm versions.

385ci Small Block Install Performance 34/36

For spark, we installed a Performance Distributors street/strip DUI distributor. This setup has a simple one-wire hookup, is hand built, and comes with a 50,000-volt coil and Dyna Module. We also ordered ours with a melonized gear for the hydraulic-roller camshaft.

385ci Small Block Performance Distributor Spark Plug 35/36

Performance Distributors also has a line of spark plug wires called Livewires; these are direct-fit 8mm diameter wires with RFI noise suppression. We opted for the under headers with 90-degree boots. These are also offered in black, blue, purple, red, silver, or yellow.

385ci Small Block Dyno 36/36

To get the final numbers, we headed over to The Carb Shop, where the Vrbancic brothers pushed our mill to the limits on 91-octane pump gas, and—drum roll please—our baseline all-motor pull made 428/434 hp/lb-ft. With the 3.25-inch pulley, it made 604/575 hp/lb-ft at 8 psi. On the smaller 2.98-inch pulley, it made 637/628 hp/lb-ft at 9.8 psi.

Last thoughts

All said and done, we were only limited by the factory block and 91-octane pump gas. While the carburetor did an excellent job of cooling the fuel prior to entering the intake, we're willing to bet we could have further improved the numbers with the addition of an intercooler and higher-octane fuel. Would the block have lasted? Maybe, but it certainly would have been a time bomb. At the end of the day, we're looking at a 600-plus-horsepower supercharged mill that's completely reliable and can be had from blower to pan for around $7,400. Note: machining and assembly charges will vary; our build added an additional $2,000, making it a total of $9,400 from start to finish.


Mena, AR 71953
Comp Cams
Memphis, TN 38118
Performance Distributors
Memphis, TN 38132
The Carb Shop
Ontario, CA
Speedway Motors
Lincoln, ME 68528
A.R.E. Performance & Machine
Simi Valley, CA 93065
Demon Fuel Systems
Wyoming, MI 49548



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