This week in Pre-owned Picks, I am looking at the forgotten Big Block chronograph from Tudor. The term “Big Block” was coined by collectors in reference to the case height. The reason for the thicker case? This was Tudor’s first line of automatic chronographs. Most interestingly, these came out twelve years before Rolex placed the modified Zenith El Primero movement in the 1988 Daytona.

Before the Oyster Date, the Chrono Time was launched in 1976. Tudor’s line-up consisted of twin-register chronographs with manually-wound movements. The advent of the automatic chronograph in 1969 sent shockwaves through many watch brands in the 1970s. Heuer, Seiko, Breitling, Buren, Hamilton, and of course Zenith had finally perfected the auto-chrono, coincidentally in the same year. Before long, movement manufacturers were hot on their tail. Valjoux stepped up to the plate and delivered the Valjoux 7750 in 1973.

Tudor Big Block head-on

The 6, 9, 12 Valjoux 7750

The three registers at 6, 9, and 12 o’clock are synonymous with the Valjoux 7750, which has found its way into a variety of models. Even today, the 7750 is the backbone of some of the most enduring designs. Unfairly, the enthusiast community dismisses the merits of a watch that uses an “off-the-shelf” caliber. Tudor used the 7750 for the Big Block from 1976 right into the ’90s. While the latest Black Bay Chrono uses the Breitling B01 powerhouse, I’d love to see Tudor reintroduce the Big Block design as part of its heritage collection.

All watches are pre-owned and picked from Chrono24. Every week we pick a few pre-owned watches from Chrono24, the largest market place for wristwatches in the world — watches that we love ourselves, or think they will be interesting to you. So, to be clear, we picked the watches, Chrono24 only send us the images without their watermark and in a proper resolution.


Tudor Chrono Time Big Block Ref. 9420/0

First up is the Chrono Time 9420/0. This great looking example is the quintessential Big Block for me. The reverse panda dial and the black bezel is big and bold and gives it a motorsports vibe. Officially named the Oyster Date, the dial on this particular example from 1980 only has Chrono Time inscribed next to the date window at 3 o’clock. While the Tudor box accompanies this Big Block on Chrono24, there are no papers.


Tudor Chrono Time Big Block Ref. 9430/0 “Exotic”

This Big Block is known to have an “Exotic” dial thanks to the grey dial and orange accents. Tudor was undoubtedly experimenting with dial spacing with the Valjoux 7750 layout. Instead of placing the model name under “TUDOR”, the text arches over the hour totalizer. The steel bezel looks like it has taken a beating, which shows character. And with box and papers, this listing on Chrono24 could have an exciting story to tell.

Tudor Chrono Time Big Block Ref. 9421/0 “Monte Carlo”

Tudor Chrono Time Big Block Ref. 9421/0 “Monte Carlo”

Last up is possibly my favorite of the bunch. Fresh from last week’s funky Rolex OP selection, I am certainly in a colorful summer mood. The “Monte Carlo” features a rich palette of orange, blues, whites, and grays. The nickname stems from the roulette wheels of Casino de Monte-Carlo, and I can certainly see the resemblance. This Big Block has a blue 12-hour bezel as opposed to the Tachymeter featured on my previous picks. The crown guards are also more squared-off against the screw-down chrono pushers — bonus points for the color-coded background used by the seller in this Chrono24 listing here.

Let me know if these picks have taught you more about the Big Block. Tudor has a great history on the Big Block on their site here. And be sure to comment on any topics you would like to see next week.