The importance of torque!

A reader asked me to clarify how the Trans-Am mentioned in the last post could run high 12s with a 2.56 axle ratio. Here's how-the engine was 461 cubes ( a .030 over 455 ) with Edelbrock heads, a Tomahawk intake and a cam with 224/234 duration ( at .050 lift ) and .473/488 lift. It had headers and a good exhaust system. The engine only put out about 460 hp on the dyno; but it made a godzilla-like 573 lbs ft of torque. Further, it made 500 lbs ft as low as 2,700 rpm. This massive amount of torque is how the car went so fast with the high ( low numeric ) gearing. It's trap speeds were between 110-115 mph, which normally would mean an e.t. in the high 11s, but the car was spining the tires literally until about 70 mph! The stiffer gears didn't help that much because the increased torque multiplication resulted in even more wheelspin. If he'd had traction bars and drag radials or slicks, the e.t. would have matched the trap speed.  I see this all the time. A friend has a Duster that he stuffed a 440 based 505 inch stroker into. He does have a drag-style suspension-subframe connectors,inboard leaf springs to clear monster slicks, pinion snubber-the whole nine yards. The car actually ran FASTER with 3.55 gears than it did with 4.30s! The reason being this 500 inch monster had plenty of torque, and with the 4.30s he was running out of rpm at the end of the track. In the "Old days" when the hot setup was a 283 Chevy bored out to 301, or a 327 with a 4-speed, yes you needed 4.11 or 4.56 gears to get a holeshot, and with the right solid-lifter cam the little motors would rev to 7 or 8 grand, so you didn't run out of rpm. Ditto for big-blocks. Remember these engines were developed to do 200 mph at Daytona in Nascar racing. The huge head ports of a 426 Hemi or 427 Ford or 427 Chevy meant you had to run them at high rpm to get maximum power. For drag racing, that meant stiff gearing. Engineers figured out that smaller ports and valves with more flow velocity at low speeds made much more low-end and mid-range torque. This is what made the original Pontiac GTO such an awesome STREET machine. When you've got 430 lbs ft of torque right off idle you don't have to rev to 7 grand. This is also why the 383 and 440 Wedge Mopars would run away from a Hemi on the street if the both had 3.23 or 3.55 gears. But give the Hemi some 4.88s-and look out! Now engine builder don't build engines like your racing at Talladega now. They build for torque instead of top-end speed. You only need a 3 grand converter and 4.11 gears if the engine doesn't have enough torque to launch the car. With a big-block or even a properly built small-block, especially with street tires- a high-stall conveter and / or stiff gears is just going to give you more wheelspin which ( Duh ) actually slows you down. You have to remember that the test bed for everything is a stock 8.2:1 L48 350 Chevy. Which puts out about 250 hp and 280lbs ft of torque. This engine is a dog in a Chevelle with 2.73 gears. 3.42s or 3.73s and a 2500 rpm converter would make it feel like a rocket, as it puts every last ounce of that 280lbs of torque to use. If the same Chevelle had a 454 and 2.73 gears, changing to 3.42s and a higher stall converter would more than likely just blow the tires off, and not give you nearly as dramatic an improvement. In fact, the car might be slower because of the massive increase in wheelspin. The reason? Even a low-compression 454 out of a late '70's or early '80's pickup makes about 400lbs of torque,and makes almost all of it right off idle for towing. So using mechanical advantage to "Fool" the car into acting like it has more torque than it does backfires, because it doesn't need any more bottom-end torque! Conversely the same applies when adding top-end power. Most modifications sacrifice low-speed torque for top-end rush. For example let's say you put a Victor Jr intake on a stock small-block Chevy. The Victor Jr makes power from 3,500-8,500 rpm. If it loses 30 lbs of torque at the bottm end-now your down to 250 lbs on that stocker. it'll kill the launch even further. And since the stock cam is going to start run out of breath about 4,500-5,000 rpm-right where the Victor STARTS to make power- the car will be a slug with the aftermarket intake. Now put that Victor intake on my ZZ4 crate motor. The ZZ4 makes 405 lbs ft of torque on the GMPP dyno. It it loses 30 lbs of torque from the new intake-it still has 375-a ton more than the stocker at it's peak. And with it's aluminum heads and hot roller cam, it will get a shot in the arm about 3 grand and pull hard to 6,500. It will probably drop 3/10s in the quarter from the mid-range and top-end boost, and the slight loss of bottom-end torque might actually help the car launch better with less wheelspin. So if your building a big-block remember that it's not a small-block. Hope this clears things up Mastermind