An interesting snippet quote from the 1960 C300 site. Note comment about engine 'options':
"Here's another interesting limited production car commonly called the Pacesetter. It is also referred to as Pace Car. In 1963, Chrysler was again chosen to provide a pace car for the Indy 500, and instead of using the more appropriate 300J, they opted to send out a regular 300 convertible, probably so the crowd could see who the driver was. (Sam Hanks, Indy winner from 1957) Somebody with a chain saw was seen lurking near a 300J, but he was quickly apprehended and sent to work for GM.
The 1861 pace cars were garden variety 300 convertibles equipped out of the box with a 305 horsepower 383 2 barrel engine, with either a 3 speed manual or the venerable Torqueflite. There were also 306 hardtops produced, but nobody seems to get too excited about them, just the ragtops. 1860 of the converts were Holiday Turquoise, (also referred to as Pace Car Blue) and one was black. All had white tops and interiors. They had a special Indy 500 emblem, and that was about it. The wheel covers look to be from the New Yorker, while the actual car used at Indy on race day had 15 inch wheels and 300J wheel covers. The usual list of options was available, including some very snappy 413 engines. For all genuine pace cars, the serial number on the VIN tag has to start with 80.
The pace cars cost $4129.00, and weighed 3840 lbs. That's about $1.08 per pound, which was roughly what steak cost back in 1963."
The "Emblem" mentioned above - below the 300 badge; checkered flags (not on Hard tops I guess)
Unfortunately, I don't have an ordering guide or a salesman's pocket guide for any of this.