It depends on the year...
New... go to any Ford dealer and order one.
60's model, you would need to go to an auction, barrett, Mecum, etc. or search a classic car autoshoppers like Hemmings, classic cars auto trader classics.
What You Could Do Is Go Online Or Go look Around Town
a 2013 shelby gt 500 gose aproximetly 200mph
( 500 horsepower ) for the 2008 Mustang Shelby GT 500
A shelby GT 500 has a 427 CI
8
to the ford website it is $48,810
yes
over 500
1967
question needs more detail
385hp
550 horsepower
397