Today it’s common to find engines from several manufacturers that share displacement figures. Engineers determined that 500 cc per cylinder is a sweet spot for efficiency with low emissions and, consequently, there are lots of 2.0-liter four-cylinders, 3.0-liter sixes, and 4.0-liter V-8s. Before that discovery, road taxes in some countries also influenced displacement. Plenty of manufacturers ended up with engines designed to fit under certain mandated thresholds. Read the full article on Hagerty.com:
I bought a stock 1977 Formula Firebird off the dealer's lot in 1977. It had a 6.6L/400 cu. in. displacement, and that was the biggest Pontiac V8 you could get that year for a Firebird. I just had to think about going fast, and the car would start speeding up.
I have a 4.9L (302 cu. in.) non-turbo Pontiac V8 in my 1981 SE Trans Am, now, and it goes plenty fast, but I have to do more than think to make the car go faster.
AMC made a 287 from 1963-66. The AMC influenced Chrysler/Jeep 4.7L V-8 is also 287 cubic inches. The AMC (Rambler) 287 came about because after 1961 they dropped the "little" 250 V-8. This left the 327 as their only V-8, and it was relegated to the Ambassador. The 62-64 Ambassador had the same wheelbase and basic body as the Classic (the "mid" size/price car, had the small American...), just different trim, grille, and taillights. The powers that be thought to let the engine be a distinguishing factor. Well, dealers didn't like that, many customers wanted more power than the 135 hp 195.6 OHV six (the 232 didn't come out until late in the 64 model year), but didn't want the "fancy" Ambassador. So the 287 was introduced for 1963, and only in the Classic. If you wanted more power you still had to get an Ambo. The 287 was 2V carb only, the Ambo 2V or 4V (with higher compression on the 4V model). I have little in quotes because externally the 250 and 287 had the same dimensions of the 327, just 1/2" less bore (the 287 had 1/4" less bore... 3.5", 3.75", and 4.0", respectively). There were lots of shared components. The cranks and rods were all forged, so it was much more cost effective to alter the bore when casting a block than to change the stroke of the crank.
AMC and Studebaker also had 304 V-8s. AMCs was created when they added about 1/16" to the deck height of the 290 (and corresponding stroke), Studebaker enlarged their 289 in the later 60s to make a 304. Don't know how they did it though...
400: But wait there is more. Were is the Pontiac 400. This motor was born as a Performance engine. For 1967, Pontiac bored the 389 out to 400 for GTO and new Firebird. And there were several versions of that Pontiac 400. In 1968 Pontiac lowered the compression, but a 2 barrel carburetor on it and for many years it was the base motor for many of the Pontiac models. And how can you leave out all those factory installed "Ram Air" versions and the over the parts counter Ram Air IV and V. And when times were a changing and the 400 had to be phase out. Pontiac came up with the W72, it was again a performance engine installed in the 1979 WS6 equipped Trans Am and Formula. So much like Chevrolet's 350, Pontiac's 400 did it all. But best of all, Pontiac's 400 came into automotive history as a performance engine and died as a performance engine.