centzontli.

aca[c]htopa çentzompa timiquizque = first we die 400 times [i.e., die a thousand deaths]
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 145.

Auh in huel nomecauh, ocatca, ca çenca miacpa in itech, onacic, in aço çentzonpa = And many times I have sexual relations with her who was my mistress, perhaps 400 times
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 139.

in aço centzompa = perhaps 400 times
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 107.

centzontli yhuan macuipohuali xihuitl = five hundred years
Anónimo mexicano, ed. Richley H. Crapo and Bonnie Glass-Coffin (Logan, UT: Utah State University Press, 2005), 9.

Centzontlamamatlatl īca tlaczaticah = He is treading on things by means of four hundred [i.e., many] stairsteps (Atenango, between Mexico City and Acapulco, 1629)
Hernando Ruiz de Alarcón, Treatise on the Heathen Superstitions That Today Live Among the Indians Native to This New Spain, 1629, eds. and transl. J. Richard Andrews and Ross Hassig (Norman and London: University of Oklahoma Press, 1984), 97.

cen xiquipilli pesos tomines ihuan caxtoltzontli pesos yhuan ontzontli pesos tomin no ixquich in tlaolli hanegas in totlacallaquil yn ticchivazque = The tribute we are to give is 14,800 pesos in money, and also all the bushels of maize. (Huejotzingo, 1560)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc. 29, 184–185.

400 = centzontli, and 800 = hontzontli (these examples show the equivalence of the numeric and textual spelling in one document from Tlaxcala)
Luis Reyes García, La escritura pictográfica en Tlaxcala: Dos mil años de experiencia mesoamericana (Tlaxcala, Tlax., Mexico: Universidad Autónoma de Tlaxcala, Secretaría de Extensión Universitaria y Difusión Cultural, Centro de Investigaciones y Estudios Superiores en Antropología Social, 1993), 216.

Auh ye ontzonxihuitl ypan chiconpohualxihuitl. axcan. yn motlallico. yn huallaque nican culhuacan yn huehuetque chichimeca. yn culhauque = It has now been 940 years since the ancient Chichimeca who were Colhuaque came and settled here in Colhuacan.
Auh ye centzonxihuitl. ypan chiconpohualxivitl ypan macuilxihuitl axcan = It has now been 545 year since... (central Mexico, early seventeenth century)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 116–119.

The use of "centzontli" is found regularly in Techialoyan manuscripts as a way of counting some number of mecatl, measuring cords (often having a length of about 50 yards, but in this context, unclear). In one variant, also in Techialoyan manuscripts, centzontli has been used to intend one count of one thousand. This is used in conjunction with dates, adding fifteen twenties and ten more twenties to arrive at the year 1500! (central Mexico, late seventeenth or early eighteenth century)
Stephanie Wood.

We see the influence of European dating methods, and especially the decimal system, on the Ajusco títulos, both with the use of centzontli for 1000 and the use of five times five-twenties (i.e. 500): "sentzontli macuilpa macuilpualtica on poal yhuan matlactle ome xihuitl" [for the year 1532 or, possibly, 1552].
See the appendix of a publication by Amos Megged, from 2008, http://hcc.haifa.ac.il/~medrens/Megged-text-07–08.pdf. While the document may speak about the sixteenth century, the copy we have is clearly later, judging not only by this Hispanization of the dating system, but also by the hand and the orthography.

yuā yalohuac chichimecapan yaque Tlaxcaldeca sentzontli tlacatli mamaCuilpohuali çeçencaberçera = And a party went to Chichimeca country. Four hundred Tlaxcalans went, one hundred from each cabercera.
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 170–171.

centzon uel acic = he succeeded in achieving four hundred (said of someone who is knowledgeable) (central Mexico, sixteenth century)
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 106–107.

centzontli = four hundred (a metaphor for considerable knowledge or achievement in books, painting, or metal working, for example) (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 224.

aca[c]htopa çentzompa timiquizque = primero nos quiten la vida mil vezes
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 144–145.

Auh in huel nomecauh, ocatca, ca çenca miacpa in itech, onacic, in aço çentzonpa = he pecado diuersissimas vezes con ella, que abran sido mas de quatrocientas
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 138–139.

in aço centzompa = quatrocientas
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 106–107.

milli centçontli ynic hueyac ce mecatl ynic patlahuac yhuan yn centçontli Xicalco milli cemmecatl yni patlahuaca... tlalmilli chinanmitl cenmecatl centçontli yn ihueyaca= la sementera que tiene cuatrocientas de largo y un mecate que quiere decir un cordel de ancho, y también los cuatrocientos en el pago llamado Xicalco, la sementera que tiene un cordel, un mecate de ancho... la simentera y las tierras de labor camellones, un mecate, un cordel, cuatrocientos de largo (Xochimilco, 1577)
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 2, Testamentos en náhuatl y castellano del siglo XVI, eds., Teresa Rojas Rabiela, Elsa Leticia Rea López, Constantino Medina Lima (Mexico: Consejo Nacional de Ciencias Tecnología, 1999), 208–209.

Auh yn cuemitli centzotli = Y la tierra, cuatrocientas [brazas] (Santa Bárbara, Ocotelulco, Tlaxcala, 1588)
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Santa Bárbara, Ocotelulco, Tlaxcala, 1588), 320–321.yn ipatlahuac. Çentzontli = extiende 400 [tlalquahuitl] (Tetzcoco, 1610)
Benjamin Daniel Johnson, “Transcripción de los documentos Nahuas de Tezcoco en los Papeles de la Embajada Americana resguardados en el Archivo Histórico de la Biblioteca Nacional de Antropología e Historia de México”, en Documentos nahuas de Tezcoco, Vol. 1, ed. Javier Eduardo Ramírez López (Texcoco: Diócesis de Texcoco, 2018), 150–151.