Stump Puller

If you've read STREET RODDER over the past few months, you've probably read the chronicles of a '41 Ford woodie's transformation from sedate stocker to keen driver. Of course re-engineering a relatively cumbersome car to fit in a highly stylized rod world raises some issues of its own, but there's an unforeseen problem--space. Even with its ample proportions, our fat-fendered passenger car crossmember won't readily accept GM overdrive transmissions without modifications. And seeing how the woodie's present owner wasn't so hot about re-engineering the factory X-member, we opted for the TH350, a smaller non-overdrive gearbox.

Not such a big compromise considering the TH350's track record, but in the world of economy and open-road comfort, a non-overdrive application calls for a pretty tall gear--a gear that usually murders performance. Since our woodie's owner wanted a little of both worlds, we had our work cut out for us. We knew we needed professional help, so we took our requirements over to Sod Bogosian's Hye-Tech Performance in La Puente, California, for his opinion. Almost instantly he prescribed a 383-inch small-block Chevy.

For those unfamiliar with the 383, it uses the abundant 350 block, but instead of using a 3.48-inch crankshaft, it uses a 3.75-inch stroke crankshaft--a dimensional holdover from the small-block 400. The extra quarter-inch of stroke combined with a .030-inch overbore yields 33 more inches, but don't get the idea we're chasing horsepower with the extra inches. Actually, by geometry and additional reciprocating mass, the 383 doesn't make much more horsepower than a 350. What it makes, however, is copious amounts of torque.

And torque is like magic. It's what gets a heavy cruiser like a woodie off its duff. It's also the force that makes a car feel spirited and fun--that neck-snapping sensation when the pedal's down. That's great in itself, but we've got ulterior motives to build gobs of torque--especially way down low where our 383 can make it.

For starters, an engine that starts making torque at a lower engine speed and maintains a broad torque band can take advantage of a higher gear and still accelerate briskly. That same numerically lower gear at highway speeds will spin the engine slower, resulting in better fuel economy. In a way, you could look at it as a poor man's overdrive.

For example, at 2,000 rpm our 383 makes 368 lb-ft of torque--as much as many healthy 350s make at peak. At that point we've only just started to stall the converter. The aforementioned 350 makes that number, but more likely at 3,500 rpm. By the mid-2,000-rpm range, our 383 is already at 400 lb-ft. At peak, we're making 431, but it doesn't just nose over after that. The torque curve is so plump it still makes 400 lb-ft at 4,700 rpm. That's just 200 rpm from its 364hp peak power at 4,900---a number that's no slouch itself.

Shift that TH350 into second at 4,900 rpm, and the tach drops to 2,900 rpm, right where our stump-puller pulls 400 lb-ft. Once we've left the line, the TH350's closer gear ratios work to our advantage over the 700; the 700-R4's larger gear ratio spreads from gear to gear and drops the engine speed lower-with resultant lower torque.

Another bonus of low-end torque monsters is that they use relatively short cam timing. In this case, we used Comp Cams' Xtreme Energy 238 cam. With 218/224-degrees duration at .050-inch and .462/.469-inch total lift intake/exhaust, we'll make power almost instantaneously. And that helps since engines that get into their torque curve quickly can use tight, efficient torque converters that stall at lower engine speeds and slip less. True, we don't get the 700-R4's lock-up torque converter advantage, but we can come close with an efficient converter. As an aside, short-timing cams also develop excellent vacuum for power brakes and aren't as vulnerable to accessory and air conditioning loads.

In concert with cam profile, nothing beats a set of well-prepped cylinder heads, and for that we opted for a set of World Products' S/R Torquer cylinder heads. These all-new castings feature 3/8-inch screw-in rocker studs, dual springs, and stainless 2.02/1.60-inch valves. The larger valves might seem large for torque production, but consider our application: A 383 is about 8.6 percent larger than a garden-variety 350. A 2.02-inch valve is about 8.4 percent larger than a 1.94, and a garden-variety 350 usually runs a 1.94-inch intake valve. There's more to it as well: Since the World Products S/R Torquer head features a 170cc intake runner, it's geared to make torque right out of the box. The S/R Torquer is also available with either a 67cc or 76cc chamber volume.

The S/R Torquer also offers the option of center-bolt or perimeter valve covers; universal end pads for accessory brackets; and one-piece, undercut, and swirl-polished Manley Street Flo valves. Don't let the features intimidate you, either; you'd barely be able to rebuild a set of stock heads for the price of the Torquer S/R. In short, the days of cobbling early heads for performance are over.

We popped over to Hye-Tech one afternoon and followed the assembly. While the parts are premium pieces from World Products, Keith Black, Eagle, World Products, and so on, this was an incredibly affordable and easy engine to build. It assembled like a stock-stroke engine with slight additional machining and only a few-hundred-dollar premium over a garden-variety 350. And even though this engine was built to address a compromise, we wouldn't dare call any affordable, low-revving small-block that makes 431 lb-ft torque at 3,900 rpm and 364 horsepower at 4,900 rpm any kind of trade off.