There were only 1000 ever built from the early "260" engine (75 built) and then when Ford came out with the 289 Shelby switched over. The 427 (about 300) came with several engines and configurations. The street model eventually had the 428 Police Interceptoror / Cobra Jet and then back to the 427 NASCAR engine for the final run of cars. The S/ C (semi competition about 50 cars) evenly divided by race prepared and a milder street version ...hence the S/C. Probably no two were ever identical with body styles , doors ,engines , leaf springs ,street or race , interiors , roll bars ,trunks , hood scoops , paint and amenities all contributing to the differences.