Why does a car with a SBC have a faster 60 foot, than the same car with a BBC? Inertia

As Wayne Gapp (from the Gapp and Roush team that won a lot of early 70's NHRA races) explains, and he was the engineer in charge of Fords 429 racing program for NASCAR and drag racing ....

NHRA was still running with the seven pounds per cubic inch rule .... under those rules, Chrysler won every race, because their Hemi was a much better motor than the Chevy or Ford. 

It wasn’t long before Bill Jenkins was petitioning the NHRA to have the rules altered to allow the use of a small block engine in a Vega at the same seven pounds per cubic inch configuration. 

The NHRA bought into the idea, thinking that it was “six of one, a half-dozen of the other”, I guess.

 Problem was, if they had consulted their physics books they would have realized that it wasn’t all that straightforward. There was a thing called inertia, which no one took into consideration. 

Simply stated, if you take a 2,700-pound big-block car and a 2,300-pound small-block car and you let out the clutch on each one, it’s the inertia off the line that determines the performance during the first 60-feet of the pass, not the horsepower. 

In other words, if you kick a cement block and a block of wood, quess which one will travel the farthest? So, naturally, Jenkins’ little Vega just jumped off the starting line and consequently it killed the Chryslers during the 1972 season.”



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