Forza 4 Muscle cars engine sound fest big test drive Buick Regal GNX 1979 Camaro Z28 Corvette c1 c2 c3 El Camino SS 454 1969 SS Coupe Chevelle SS--454 Impala SS 409 1970 IROC--Z ZR--1 Stingray 427 Charger R/T Challenger R/T Daytona HEMI Dodge King Cobra Thunderbird GT Coupe 1965 XB Falcon GT Boss 429 Mustang Mach 1 GT40 MkII Hurst/Olds 442 Barracuda Formula--S Plymouth Cuda 426 HEMI Firebird Trans Am GTA SD--455 1977 1987 1973 GTO Judge GT--500KR 1968 Cobra 427 S/C Daytona Coupe Horison Indianapolis Motor Speedway Infineon Laguna Seca Nurburgring GP Road America Atlanta Sebring