1970 was the last year that engines were not affected by emission requirements and insurance ratings. Starting from 1971 engine were detuned to satisfy emission requirements and insurance ratings. (The 426 Hemi is the only exception it was never detuned.) However, most 1971 engines were only marginally less powerful than 1970 engines. The real damage would come in 1972 when engines were dramatically less powerful than the year earlier (and the 426 Hemi and the 440 6-Barrel disappeared). Still if you wanted the absolutely most powerful engine in the most recent car 1970 was the year to do it. This brings us to the 1970 Road Runner. This is also the last year for the boxy style body of the Road Runner. 1971 Road Runners have the fuselage style body. I actually like both the boxy style and the fuselage style but the boxy style really looks like what I think a muscle car should look like. Although not very aerodynamic (the fuselage style is much better aerodynamically) the boxy style looks muscular and powerful. Moreover, this car has real character with the Road Runner cartoon character, beep beep horn and Air Grabber with sharks teeth. Engine options included the 426 Hemi (the same 426 Hemi was also available in 1971), RB 440 6-Barrel (the 1971 RB-440 6-Barrel was 5 horsepower weaker) and the B 383 (the 1971 B 383 was 35 horsepower weaker). Of the 68-70 Road Runners I like the look of the 70 rear end the best. The look of the rear end is the only thing that dramatically changed each model year and the the look of the 70 rear end really matches the boxy body styling. For me the 1970 Road Runner is exactly what I would want in a muscle car – has lots of power, looks like it and sounds like it.