Being an Aussie I would say the Falcon GTHO Phaze III, which was designed for production touring car racing & in fact to win one race the 500 mile Hardie Ferodo 500 at Bathurst. However to make all the mods race legal they had to sell so many for the road - 1500 GTs & arround 300 homogulated with the racing mods as Falcon GTHO Phase IIIs.
They had a top speed of 160mph & did the quarter mile in 14 secs with the same gearing. However as there were 4 different gear ratio options for the Toploader 4speeds they were sold with, Some have a lower top speed but accelerated faster & vice-a-versa. They are extremelly rare today as a good proportion were written off in racing, so most on the road are fakes. Genuine ones in concours condition are worth about $50 000 today.
Here are some limks on the Falcon GT & the Falcon GTHO PhaseIII, Which in its day was reputed to be the fastest production 4 door sedan in the world, What with its Cleveland racing engine that reved all the way to 7000 revs in stock GTHO form.
http://www.netspace.net.au/~manc/MOFFAT1.html appears to be a Newspaper aticle about the GTHO Ph1 (XW{69}351W), Ph2 (XW{69}351C), & Ph3 (XY{71}351C) & their success at Bathurst (a 500 mile production touring car race).
http://www.fl.net.au/~johnk/ho.gif A very famous photo that appeared in Australian newspapers, taken by a 'Wheels' magazine staffer, during a test drive. The photo is taken from the aspect of someone sitting in the rear seat, leaning over the drives shoulder. In the photo you can look down the bonnet, past the 'Shaker' bonnet scoop & see the Hume highway, but if you look down at the dash you'll see the tacho at 6700rpms & the speedo at its maximum - 0ver 140mph (I don't know if its true, but someone told me, that by caculating the revs against the gear & diff ratios the car was doing 158mph).
This cause a furor with the media & politicians, forcing Ford from bringiing out a GTHO phase 4 variant of the latest XA(72) Falcon, after they already made 5 cars (which BTW had a top speed of nearly 180 mph).
http://falcongt.com The West Astralian Falcon GT Club.
http://members.tripod.com/~Wardman/gthistory.htm Pictures of the various Falcon GT models.
http://www.falcongt.com.au A Falcon GT restoration business, good photos.
http://www.fl.net.au/~chris A site that has information about old & new Falcons, including the MadMax cars. Yest that's right Mad MAX, Mel Gibson himself drove an Aussie Falcon, however most Falcon GTs were 4 door sedans, but a few Falcon GT 2 door coupes were made arround the mid 70s, plus 2 of the 7 infamous Falcon GTHO Phaze IV race cars were 2 door coupes too.
Other great Musclecars would be the original 289(W)V8 AC Cobra (which was in fact an English car, just with Canadian Windsor V8 engines) & the later 427 AC Cobra. Also the road goingAluminium hand beated Ford GT40 Mk IV LeMans racers (they made a limited amout of MkIVs for the road). The early ones also had 289 Windsor V8s, while later ones had 427 big blocks. BTW AC still make hand beated aluminium bodied Cobras today in England.
Also one mustn't forget the Shelby Mustang GT350 & GT500, plus the Hertz rent-a-racers. Also the 426 Hemi Road Runners & Super Bees with thier outrageous rear wings & aerodynamic front aprons, were bloody amazing vehicles too. Plus there's GM & the original Fuel injected 327 V8 1963 Stingray & the GTO & of course the 455SD (of the famous Radio Birdman song).