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




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