How Many YF3 Options, Based On Body Style, Were Sold?
Chevrolet did not keep, or at least did not release, information on how many of any particular body style were sold with what specific options. But this is a trick question, the YF3 Heavy Chevy option was only available with the base Chevelle/Standard 2-door sport coupe. Several V8 engines (sorry, no 454 engines though) & transmissions were available but those same engines and transmissions were available in other Chevelle series' and models as well so there's no way to know something like how many 350-2 engines with a TH350 transmission were ordered with the Heavy Chevy option.
Many published production numbers come from an old publication of Tailfins & Bowties, by Len Williamson, that is generally accepted as being the most accurate for this type of data since he had access to Chevrolet's archives of information.
The regular production option (RPO) YF3 was available in both 1971 and 1972. The 1971 models didn't hit the streets until around March of 1971 and with not much hype or promotion so the 1971 model year production numbers are naturally lower than the 1972 model year. Production figures show 6,727 sold in 1971 and 9,508 sold in 1972.
GM of Canada documentation shows 1,445 13437 Chevelle sport coupes were built in Canada in 1971. Of those 541, over 1/3rd, were YF3 equipped.
The images below are from GM's Restoration Kits for 1971 & 1972 describing the YF3 Heavy Chevy option and what it included in both years. The Engines and Transmission section for 1971 is included to show what engines and transmissions were available with the Chevelle/Standard series and which were not available. The 1972 model year included the same engines and transmissions but it should be noted the 1972 engines were rated differently for horsepower.