Special k,
Every S/C did NOT come with a 427. the race chassis were sitting emty when the decision was made to create the S/C, and they used whatever engines(427/428) were available as they were sold off. however there is no documentation to this exept a few remaining invoices.
many of the cars exchanged the 428 for a 427 at a later date. I dont think any one really knows the original mix.
karl