The heck with spec

Paint is about the only distinguishing feature of modern Indy race cars. That wasn't always the case. All teams run an ethanol-fired Honda 3.5-liter V8 engine, up from 3.0 liter in 2006. Honda says the displacement bump should help engines go longer between rebuilds and give more midrange torque for races on road courses and short ovals. A Pratt & Whitney 550-hp helicopter turbine engine powered the 1967 STP car. Driver Freddie Agabashian in the 1952 Kurtis-Kraft Cummins Diesel Special. The 1934 Cummins Diesel Indy car. Vehicles in the IndyCar Series are a study in strict conformity to ever-more stringent specifications. Chassis this year come from one of two builders: Dallara and Panoz. Honda 3.5-liter V8 engines power the whole field. No doubt, the approach levels the playing field, lowers costs, and makes for spectacularly close finishes. But the Indy-car spec was not always so tightly defined. Race teams and regulators back in the day took greater engineering risks that sometimes didn't pan out, but in others, far exceeded expectations and forever altered the sport. Advancements that gave pioneering teams unfair —albeit brief — competitive advantages as well as the inevitable crashes prompted further changes. With that in mind, consider some notable hits and misses of the Greatest Spectacle in Racing, as well as what's new this year. 2007 — Ethanol supplants methanol Following a successful transition to a 90/10 (methanol/ethanol) blend in 2006, Indy cars this year switch to 100% ethanol for racing fuel, the same stuff blended with gasoline and sold at the pump. The move, designed to spur the U.S. ethanol industry, is the third major change in fuel. The first came in 1965 following a fiery crash the year before that killed two drivers and prompted racing officials to change fuel from gasoline to methanol and later