When the muscle car era was launched, horsepower was only half the story.

Think about it: How was the muscle car created? Most authorities point to the moment when Pontiac engineers, led by John DeLorean, transplanted their big 389ci V-8 from the heavy Catalina into the lighter LeMans body, producing the 1964 GTO. So the powerful engines were already in hand, or were at least well on their way. The second component in power-to-weight ratio, the other half of the muscle car equation, if you will, was weight.

And just like the horsepower claims of the classic muscle car era of 1964 to 1972, the weight figures are subject to myth, legend, and old bench racers' tales, too. Back in the day, manufacturers and magazines alike pumped out volumes of confusing and often conflicting weight specifications. Terms such as shipping weight, curb weight, and test weight had flexible meanings or were even thrown around interchangeably. As a result, many owners received a shock the first time their cars crossed the scales, discovering that their machines weighed many hundreds of pounds more than they thought. Surprisingly enough, some of the faulty info continues to this day.

So what did the classic muscle cars weigh, really? We can start by nailing down some of the historic technical terms used to specify weight. These are generalized terms that vary among sources, but broadly speaking:

Dry Weight: As the name indicates, this is the vehicle's actual weight with an empty fuel tank and no coolant, lubricant, or other fluids, and without passengers or cargo, but otherwise complete and ready to run.

Shipping Weight: This value was originally used for calculating vehicle freight costs from the factory to the dealer, but was also adopted by some race sanctioning bodies for classification purposes. It does not include fuel, fluids, passengers, or cargo, and typically also excludes optional equipment such as air conditioning, power steering and brakes, etc. As a result, shipping weight can understate an individual vehicle's actual weight at the scale by hundreds of pounds.

Curb Weight: This is the weight of the vehicle including all fluids and a quantity of fuel, usually a full tank but alternately half a tank or some fixed number of gallons. Curb weight can be a declared specification from the manufacturer, as found in a sales brochure. Or it can be an observed value as measured on a scale by an automotive publication or other source, as reported in a magazine road test.

Test Weight: Also known as road weight or gross weight, this is the full, actual weight of the vehicle recorded when performance test results are obtained. The value includes a full tank of fuel, the driver, an observer if present, plus fifth wheel or other test gear. Since this figure is used to calculate values, such as road horsepower, it must be a true accurate total.

Gross Vehicle Weight Rating: This is the total weight of the vehicle plus its maximum allowable passenger and cargo capacity. This spec is not terribly relevant in the high-performance world, more of a truck thing, obviously, but is noted here simply for purposes of definition.

These methods each have their purposes, but unfortunately, they weren't employed with any real uniformity or clarity. Sometimes the method wasn't even stated. Nevertheless, at least one period source, Car & Driver magazine, was aware of the issue, and conscientiously reported multiple values in its road tests for a few years. To give you a general idea of how these values scale relative to one another, here are C&D's figures for the 1965 Mustang 2+2: dry weight 2,760 pounds, curb weight 2,877 pounds, test weight 3,175 pounds. Here's a second example, 1965 Corvette: dry 2,975 pounds, curb 3,180 pounds, test 3,500 pounds. When you consider that gasoline weighs around 6 pounds per gallon and humans weigh anywhere from 120 to 250 pounds, very roughly, the discrepancies are fairly easy to sort out in a general way—as long as you know which value you have been dealt.

So which method is the most accurate and useful? We place our vote with curb weight. It's pretty hard to get down the track or even around town without gasoline or lubricants, so dry weight is out. And unless it's a stripped-down base model, shipping weight does not reflect the vehicle as equipped. Test weight is realistic, but introduces a large variable, driver weight, as we saw above. So as we see it, curb weight plus your personal weight will get you closest to the true weight of your vehicle on the road.

Just for fun, here are some weight figures for a number of popular vehicles from 1964 to 1972. Included are year, make, model, displacement, transmission type, and curb weight (observed whenever possible). The sources are original road tests published in Car & Driver, Motor Trend, and Car Life in those years. Unless otherwise stated, all the vehicles are two-door hardtops.

Now, the truth is there is only one way to know for sure how much your particular vehicle actually weighs: Put it on a scale. And honestly, we don't expect to settle any arguments with this info. But who knows, maybe we can start a few more.

RideTech Weigh-In

That was then, and this is now. As we add stuff like bigger engines, rollbars, big brakes, steam-roller wheels and tires, sound deadening, and aftermarket A/C—not to mention pounds around the middle—things change. Sometimes it's for the better, and sometimes it's just mass in the wrong place. If you're not sure what or where your poundage is, you can weigh your car for free at any event RideTech attends. They've got four-corner digital scales that can not only give you an overall weight, but tell you front/rear weight balance, and individual corner weights. Moreover, in the four years since RideTech started their weigh-in program, they've amassed data on over 2,500 cars ranging from street rods and trucks to muscle cars and late-models. (All of this data is available to view on RideTech's website, www.RideTech.com, under the "Tech" section, and is cataloged by year and make.)

We recently took Project Nova—our 1968 Chevy II—to RideTech's weigh-in, and got the exact numbers. With a full tank of fuel and no driver, it was 3,419 pounds, with 1,857 on the front (54.31 percent) and 1,562 (45.69 percent) for the rear. That's a far cry from the 2,995 pounds of advertised curb weight for an "average" 1968 Chevy II V-8 coupe as published in Consumer Guide's Encyclopedia of American Cars, a tome that's often quoted, but in this case was way wrong. Where does our Nova fall in the spectrum? Compared to the six other 1968-72 Novas in RideTech's database, ours was heavier than all but one, most likely due to a full tank of fuel and a mild steel rollbar. That's still a lot lighter than the 3,835-pound 2010 Camaro SS and 3,817-pound 2009 Mustang GT also in RideTech's database! Johnny Hunkins