Porsche 911 Forever Young by Tobias Aichele listed the Stuttgart license plates and dates used for a number of the 911 prototypes. This information provided an interesting glimpse into when the different license plate letter series, (S-SK, S-TV, S-UN, etc.) may have been first used during 1964.
For 1965 and later years, information on when the subsequent letter series, S-UV through S-ZZ, S-A to S-Z and back to S-AA, were first used was gleaned from 911 competition cars as well as other Porsche competition cars. A couple of entries from Kraftfahrzeugbrief registration booklets, S-J 3063 first used 31 May 1968 and S-M 2188 first used 1 April 1969, were included as well.
Please send me any additions or corrections to these tables. I hope this is of interest to others.
Sources:
Werks 911 Rally Cars 1965-1972 thread
https://www.early911sregistry.org/fo...cars-1965-1972
Cars with Factory Plates thread
https://www.early911sregistry.org/fo...factory-plates
Porsche race and rally cars
www.racingsportscars.com, targapedia.com, https://www.ewrc-results.com/
others as noted
1964
S-SK 726, February 1964, 901 Prototype 4, 13324
S-SX 564, February 1964, 901 Prototype 7, 13327
S-TC 1, April 1964, 13325
S-TV 112, July 1964, 901 Prototype 8, 13328
S-UN 476, November 1964, 901 Prototype 13, 300002
S-UP 934, December 1964, 902 Prototype 11, 13352
Source - Porsche 911 Forever Young, Tobias Aichele p 54-61
Source - S-TC 1 - https://www.early911sregistry.org/fo...th-translation
1965
S-UV 333, January 1965 Monte Carlo Rally , 911, 300055
S-UX 911, 11 March 1965 print date for Sales booklet W29-5
S-VP 102, May 1965 Targa Florio, 906-008 kangaroo
S-VS 363, June 1965 Le Mans, 904/6
S-VW, July 1965 Cesana-Sestriere Hill Climb, 906-008 kangaroo
1966
S-WX 449, 911, January 1966 Monte Carlo Rally, 303075
S-WX 450, 911, January 1966 Monte Carlo Rally, 303076
S-WX 451, 911, January 1966 Monte Carlo Rally, 303085
S-XR 42, 906, May 1966 Targa Florio
S-YC 529, 911S, August 1966 auto motor und sport issue 19
S-YC 529, S-YC 532 on 67Ss, S-YC 911 on early targa, 24 August 1966 in “hobby - Das Magazin der Technik” Nr. 18/66
S-YC 529 - https://www.early911sregistry.org/fo...th-translation
1967
S-YS 847, 911S, January 1967 Monte Carlo Rally, 306656S or 306657S
S-YS 848, 911S, January 1967 Monte Carlo Rally, 306655S
S-YS 849, 911S, January 1967 Monte Carlo Rally, 306656S or 306657S
S-ZL 307, 911R, April 1967, 11899002R
S-ZP 740, 911S, June 1967 24 Hours of Le Mans, 303108S
S-ZZ 826, 911S, August 1967 Marathon de la Route
S-ZZ 827, 911S, August 1967 Marathon de la Route
S-ZZ 829, 911R, August 1967 Marathon de la Route, 307671 prototype R3
S-A 2522, 911R, October 1967 Monza Record Run
S-A 2522 https://www.autodiva.fr/forum/viewto...1574&start=480
1968
S-C 9166, 911T, January 1968 Monte Carlo Rally, 11820472
S-C 9167, 911T, January 1968 Monte Carlo Rally, 11820433
S-E 8052, 911L, April 1968 DDR Rally, 11810409
S-J 3063, 911S, 31 May 1968 Kraftfahrzeugbrief, LWB 320-013 prototype
S-K 2403, 911R, November 1968 Tour de Corse, 11899005R
S-J 3063 - https://www.early911sregistry.org/fo...=1#post1127123
1969
S-L 2263, 911S, January 1969 Monte Carlo Rally, 119300529
S-L 2264, 911S, January 1969 Monte Carlo Rally, 119300530
S-L 2265, 911S, January 1969 Monte Carlo Rally, 119300548
S-M 2188, 911S, 1 April 1969 Kraftfahrzeugbrief, 119200623
S-P 7435, 917, August 1969 1000km Zeltweg, 917-009
S-R 1621, 914, September 1969 factory photos
S-R 3000, 914, Ferry Porsche received this car on his 60th birthday (Sept 19, 1969)
S-P 7435 - http://www.austroclassic.at/index.ph...7756&Itemid=46
S-R 1621 https://www.early911sregistry.org/fo...l=1#post876275
1970
S-T 5704, 911S, January 1970 Monte Carlo Rally, 9110300001
S-T 5705, 911S, January 1970 Monte Carlo Rally, 9110300002
S-T 5706, 911S, January 1970 Monte Carlo Rally, 9110300003
S-U 3912, 917, 16 March 1970 Targa Florio Test
S-W 1947, 914-6 GT, August 1970 Marathon de la Route
S-X 7495, 914-6 GT, November 1970 RAC Rally
1971
S-Y 7714, 914-6 GT, January 1971 Monte Carlo Rally
S-Z 7941, 911S, February 1971 Rally Sweden, 9111300565
S-AA 3128, 911S, April 1971 Safari Rally
S-AA 3129, 911S, April 1971 Safari Rally
S-AA 4825, 911S, April 1971 Safari Rally
S-AA 4826, 911S, April 1971 Safari Rally
S-AA 4827, 911S, April 1971 Safari Rally
1972
S-AK 1336, 911S, January 1972 Monte Carlo Rally, 9112300041
S-AK 1337, 911S, January 1972 Monte Carlo Rally, 9112300047
1973
S-AR 7909, 911 RS, April 1973 East African Safari Rally, 9113600285
S-AR 7910, 911 RS, April 1973 East African Safari Rally, 9113600288