I talked to a guy today about 12-bolt rearends. He said that the very first Camaro 12-bolt rearends were made using Chevelle centersections because of some delay in production. Is this just made up or is there some truth in it ? Never heard it before.
Something like the first 1964 Chevy II 327 engine-blocks useing the 283 casting (since that 283 was a thickwall-block), so I guess anything would be possible.