I was looking at an expired eBay auction for a 67 Caprice coupe, L35 M20 car. The engine code was T01113IAR. I realize that generally the 3-letter suffix didn't appear until 1970 models except for some late 69s and also certain Holley equipped 1966 big blocks. Normally I would expect an IA code for a manual L35 engine, but IAR? What gives?