I submit to you the 1970 Chrysler 300 Hurst @ 224.7 inches long.
http://oldcarmemories.com/1970-chrys...2-tons-of-fun/
"Only two full-size muscle cars exceeded this length. One was the 1969-1970 Mercury Marauder which had a length of 221 inches. The other was
the 1970 Chrysler 300 Hurst (sometimes referred to as the 300H) which by far was the biggest muscle car ever produced – it had a length of 224.7 inches, width of 79.1 inches, and a wheelbase of 124 inches. This car was so big that even in the era of large American cars it was a behemoth."