Budget Supercharged Small-Block Chevy Engine Build - 445HP For $3,995

Combine a used 350ci small-block... 

   

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Combine a used 350ci small-block and a Weiand mini-blower and you have an affordably powerful combination.

We can hear the hue and cry already-"Man, not another small-block Chevy story!" We hear you, but when was the last time you attempted to build a complete blower motor from carburetor to oil pan for under $3,995? We even avoided digging too deeply in the used-parts bin. In fact, the only previously owned parts in this whole buildup are the short-block, a portion of the carburetor, and the distributor. Everything else was purchased new with an eye toward balancing the budget below $4,000. As you can see from our price chart we just barely came in under the budget, but the numbers add up.

That's the financial side of the story, but the much more interesting information is based solely on the dyno side of things. The idea was to build as much power as we could without just throwing dollars at it. The star of the show is clearly the Weiand blower, but with a twist. No, the impellers are still straight, but Weiand has created a new Vortec cylinder head-compatible intake manifold. That opens up several horsepower-friendly doors, so we decided to see how much power we could make on our peanut butter-and-jelly budget.

You can skip to the power curve, but the numbers crunch down to a stout 455 lb-ft of torque at a reasonable 3,900 rpm, while horsepower clicks in at 445 ponies at 6,000 rpm. This creates an outstanding 2,100-rpm broadsword powerband that would make this a superb street small-block in front of a tight- converter automatic. Think how this combo would roast the hides at will and still offer great street manners. All that's left to do now is fill you in on the details.

We started with a medium-mileage...        read full caption We started with a medium-mileage standard-bore short-block that we bought for $100. We removed the pistons, rods, and crank; cleaned everything; and did a quick inspection.

After cleaning the pistons,...        read full caption After cleaning the pistons, we bottle-brush-honed the cylinders, cleaned the entire block again, and began the reassembly using new Federal-Mogul rings and bearings. Assume you will need 0.001-undersized mains and rods if you don't grind the crank.

With the rotating assembly...        read full caption With the rotating assembly in place, we installed the new Crane cam and lifters. We used Crane's special assembly lube and oil additive to protect the cam during break-in.

Vortec Head Tricks
The whole reason for doing this story revolves around the Vortec heads. These are iron heads with 1.94/1.50-inch valves that offer better intake-port flow characteristics than the older, iron Bow Tie heads. But the real beauty of these castings is that they are very affordable. The stock assembled iron Vortec (PN 12558060) sells through Scoggin-Dickey Performance Center for just under $500 for the pair. You can barely rebuild a stock set of iron heads for that price. Unfortunately, the Vortecs present a couple of restrictions on their use.

First of all, the Vortec family of cylinder heads uses a specific intake bolt pattern requiring a matching intake manifold. That's why we got excited when Weiand offered a mini-blower manifold for the Vortec. The next point that actually played in our favor was the Vortec's 64cc combustion chamber. Normally, with four-valve relief, flat-top pistons and composition head gaskets, a standard-bore 350 would have 9.7:1 compression, which is a bit high for a pump-gas blower motor. But because the stock cast pistons in this engine employ both a dish and a horrible chamfer around the piston's outside diameter, the static compression ratio is more like 8.6:1, which is far more blower-friendly.

Since we wanted to run a mild camshaft that would generate almost a half inch of lift, we knew we would have to modify the Vortec heads. The stock Vortec's Achilles heel is that the valvespring/retainer/seal combination is limited to a maximum of about 0.460 inch of valve lift. One solution is to change valvesprings, but that involves expensive machining operations. This is where Scoggin-Dickey enters in the game again with a set of affordably priced heads that are already modified for additional valve lift and come with slightly stiffer valvesprings to accommodate a bigger cam. If you have experience modifying cylinder heads you might be able to do the work yourself for less coin, but assuming you don't have the specialized cylinder-head tools, the Scoggin-Dickey heads are an excellent bargain at $680 for the pair, and all you have to do is bolt them on.

Scoggin-Dickey sent us a set...        read full caption Scoggin-Dickey sent us a set of its modified Vortec heads, which are equipped with better valvesprings that will accommodate more valve lift and not go into valve float. We also used thin, Fel-Pro shim head gaskets (PN 1094), to help the compression ratio.

The Vortec heads require specific...        read full caption The Vortec heads require specific intake-manifold bolts, which ARP makes for Vortec applications. You could also use factory intake bolts if you wish.

Vortec heads require guided...        read full caption Vortec heads require guided rocker arms employing two small rails that align the rocker over the valve-stem tip. Pioneer makes stamped, guided 1.6:1-ratio rockers, which we used on this engine.