This page-by-page annotation is organized by sections, as delineated by the seven squares (sprockets) which separate each section. The page numbers for this page-by-page annotation are for the original Viking edition (760 pages). Editions by other publishers vary in pagination the newer Penguin editions are 776 pages; the Bantam edition is 886 pages.
Contributors: Please use a 760-page edition (either the original Viking edition with the orange cover or the Penguin USA edition with the blue cover and rocket diagram there are plenty on Ebay for around $10) or search the Google edition for the correct page number. Readers: To calculate the Bantam edition use this formula: Bantam page # x 1.165. Before p.50 it's about a page earlier; as you get later in the book, add a page.
Finally, profound thanks to Prof. Don Larsson for providing the foundation for this page-by-page annotation.
61.19 Sodium Amytal
Also known as "truth serum", Amobarbital is a drug that is a barbiturate derivative. It has sedative-hypnotic and analgesic properties. It is a white crystalline powder with no odor and a slightly bitter taste. It was first synthesized in Germany in 1923. If amobarbital is taken for extended periods of time, physical and psychological dependence can develop.
61.25 Got a hardon in my fist...
This song goes right along with the tune of "Bye Bye Blackbird," starting with the "Pack up all my cares and woe..." refrain that, in this YouTube, begins at about 0:52.
The sarcastic nickname for a lapel pin issued at honorable discharge from the US armed forces in WWII, depicting a screaming eagle inside a wreath. "Ruptured" = herniated.
The town of Roxbury was founded in 1630 by the author's ancestor William Pynchon, and is now a neighborhood of Boston, MA. It had been an immigrant neighborhood for generations before African-Americans began to migrate from the South after WWI. While writing GR, Pynchon would certainly have been aware of rioting there at the time of Martin Luther King Jr.'s assassination in 1968. 
63.03 Roseland Ballroom
Not the better-known Roseland Ballroom in New York City, but the one on Massachusetts Avenue in Roxbury. "The stretch of Mass. Ave. between Huntington and Columbus was, by the late ’40s, Boston’s answer to 52nd Street in Manhattan -— with not only the Roseland, but the Savoy Café, the Hi-Hat, Wally’s, and a handful of smaller clubs."
One of the first mass-produced carbonated soft drinks in the United States. In its advertising, it used “Make Mine Moxie!” advertising jingles, the slogan “Just Make It Moxie for Mine”, and a "Moxie Man" logo. Uncapitalized, "moxie" became slang for energy and daring. The brand suffered a significant decline in sales during the 1930s.
63.22 Red, the Negro shoeshine boy
Stating the obvious, Red is Malcolm X, whose nickname "Red" referred to his hair color -- a dark cinnamon brown. In February 1941 Malcolm moved to Boston to live with his older half-sister, worked a variety of jobs including shoeshine and became involved in Boston's "underworld fringe," pimping among other things. 
63.32-37 "Yardbird" Parker is finding out [ . . . ]
Refers to jazz saxophonist Charlie Parker. Correspondent Igor Zabel offers the following addition to Weisenburger's note on this passage: "On one of Parker's CDs (Swedish Schnapps +), I found the passage which was quoted by Weisenburger after Max Harrison, but slightly different, and it is interesting because Parker directly mentions Cherokee: 'Well, that night, I was working over 'Cherokee' and, as I did, I found that by using the higher intervals of a chord as a melody line and backing them with appropriately related changes, I could play the thing I'd been hearing. I came alive.' The quotation is taken from 'Hear Me Talkin' To Ya'."
64.19 "'Slip the talcum to me, Malcolm!'"
This homoerotic scene seems based on some facts. It is known that Malcolm X prostituted himself for money and according to Bruce Perry's biography, Malcolm: The Life of a Man Who Changed Black America (Station Hill, New York, 1991) he had various homosexual liaisons throughout his life. Interestingly, Malcolm worked as a butler to a wealthy Boston bachelor, William Paul Lennon. According to Malcolm's sidekick Malcolm Jarvis, he [Malcolm] was paid to sprinkle Lennon with talcum powder and bring him to orgasm.
64.24 "any of those Sheiks in the drawer?"
Sheik was a popular brand of condom. "Other brands evoked an exotic, Far Eastern world of harems and belly-dancers that automatically triggered sex in many adult minds... Giant [firm]s like Julius Schmid, who made Ramses and Sheiks..." 
As well as selling accessories, hotel bellboys, shoeshine men and washroom attendants could often arrange contacts with amiable women ("another luck-changin' phone number there, Red..?")
64.30 Red Malcolm the Unthinkable Nihilist
At this depth in the American dream, fears of ideology, race, and class are indistinguishable: after all, a Harvard man in an Arrow shirt is about to be anally gang-raped by Negroes while jazzmen above set fire to a song about love for a Cherokee maiden...
65.09 Burma-Shave signs
Burma-Shave was an American brand of brushless shaving cream, famous for its advertising gimmick of posting humorous rhyming poems on small, sequential highway billboard signs. 
65.15 "Gobbler" Biddle
The Biddles are one of the leading families of Philadelphia, who sometimes vacationed in the Berkshires. Specifically, the "Gobbler" could be Nicholas Biddle (Harvard, 1944).
Interestingly Francis B. Biddle (Harvard College 1909, Harvard Law 1911) was US Attorney General (1941-1945) at this time. FBB was responsible for directing the FBI to arrest "enemy aliens" leading to Japanese-American internment camps; served as the primary judge during the Nuremberg war crimes tribunal; and authored of The Fear of Freedom and other works.
65.16 Fu’s Folly in Cambridge
Although, as Weisenburger notes, the character is named for Fu Manchu (who is an important reference for Pointsman later in the novel), it should be recalled that there was also a "Fu" who was a member of the Whole Sick Crew in V.
Resembles the old Young & Yee Restaurant (now closed) at 27 Church Street, Harvard Square, Cambridge, MA, which for over 40 years slopped greasy chop suey. An anachronism to the novel's time period, yes, but perhaps an inspiration to the author.
65.33 Jack Kennedy
JFK (whose father, Joseph P. Kennedy Sr., was US Ambassador to the UK in 1938-1940) is said to be in Slothrop's Harvard class. Estimating, Slothrop was born ca 1917-18 and entered Harvard in 1936, the year of Harvard's tricentennial.So both were in their mid-20s, Kennedy a PT boat commander in the Pacific, during the action in GR. The poignant "might Jack have kept it [the harmonica] from falling, violated gravity somehow?... yes it seems Jack might have" can be read as a retrodiction from the Vietnam War and urban-riot years of GR's composition: some believed that American life would not have taken its darker turn had Kennedy not been assassinated in November 1963.
Contrary to Weisenburger, Kennedy’s first book was titled Why England Slept (not "When") [Corrected in 2nd edition]
The Capehart automatic phonograph with a turn-over mechanism was the epitome of luxury phonographs, technical excellence and supreme electronics in the 1930s and 40s.
67.32 Red Devil Lye in his hair
Lye (sodium hydroxide) was an ind=gredient in home-made congolene or "conk" hair-straightening mixtures.
67.34-35 Not "archetypal" westwardman, but the only
An explicit nod to psychologist Carl Jung, and beyond him to the Platonic strain in philosophy: that behind all the multiplicity, variety and changing detail of daylit life, there are (in our minds and/or metaphysical reality) singular, unchanging forms: in this case, the primal explorer-mountain man-cowboy-gunfighter hero.
Pynchon also works this trope in the other direction whenever he assimilates a character to archetypes in pop culture (often film), as when Jessica gave Roger "her Fay Wray look"(57) and Roger played the drooling Dirty Old Man (59).
68.01 Half an Ark’s better than none.
For Crutchfield, there is only one of everything, as opposed to two of every animal on Noah’s (whole) Ark. (And how much use is half an Ark in a flood, anyway?)
68.13 Red River Valley
From this valley they say you are going
We will miss your bright eyes and sweet smile
For they say you are taking the sunshine
That has brightened our pathways awhile
Come and sit by my side, if you love me
Do not hasten to bid me adieu
Just remember the Red River Valley
And the cowboy who loved you so true
69.02 terre mauvais
French "terre mauvaise" - the "badlands". A rare case of TRP misspelling a foreign word.
69.14 a bandana of the regulation magenta and green
The coal-tar derived colors of organic chemistry that resonate throughout the novel.
The visual clash between these colours appears elsewhere - 'A bit of lime green in with your rose' 12 Pynchon seems to associate positive things with these colors - see Against the Day particularly - as he does with bandanas. A-and bananas. For more on colors....
69.16 Rancho Peligroso
"Dangerous Ranch": evokes the Siege Perilous of the Arthurian Grail legend as well as Rancho Notorious, a 1952 Western directed by Fritz Lang and starring Marlene Dietrich. See note at V321.06-07
69.27 callipygian rondure
callipygian -- having shapely buttocks, originally used in conjunction with the noted statue of Aphrodite (which is itself a play on "Afro" and "Venus"), the "Venus Kallipygos". This language parodies the typology of "scientific" racism from the late 19th and ealy 20th century.
rondure -- a circular or gracefully rounded object.
69.32 Toro Rojo
70.15 One mestiza. One criolla
Mestiza: woman of mixed race, especially mixed of European and Native American ancestry.
Criolla: woman of "pure" Spanish ancestry, but born in the New World.
70.29 the Ardennes
The Ardennes is a region of extensive forests, rolling hills and ridges formed within the Givetian (Devonian) Ardennes mountain range, primarily in Belgium and Luxembourg, but stretching into France... The strategic position of the Ardennes has made it a battleground for European powers for centuries... in both World War I and World War II, Germany successfully gambled on making a rapid passage through the Ardennes to attack a relatively lightly defended part of France. The Ardennes was the site of three major battles during the world wars – the Battle of the Ardennes in World War I, and the Battle of France and Battle of the Bulge in World War II. Many of the towns of the region were badly damaged during the two world wars. 
70.32 Newton Upper Falls
Newton Upper Falls is a village situated on the east bank of the Charles River in the city of Newton, Massachusetts, in the United States. 
A regional name, dropping the first "c" in "Arctic," for metal-buckled rubber galoshes.
71.02 Beacon Street
Beacon Street is a major thoroughfare in Boston, Massachusetts and several of its western suburbs. Beacon Street in Boston, Brookline, Brighton, and Newton is not to be confused with the Beacon Street in nearby Somerville, or others elsewhere.