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:
A variation on this discussion: I believe Ford/Lincoln/Mercury covered the 7-liter zone with at least six different V-8 engines, measuring 425, 426, 427, 428, 429, and 430 cubic inches.
'57 and '58 Dodge and Desoto 392 hemi, International Harvester 392, plus current Dodge 392 hemi (6.4L) "Apache"
IH 304 and AMC 304
Bonus Bonus to the 383-Mercury 383 "Marauder"
My IH shop manual has a million mile maintenance schedule in it with various overbores due to the extremely thick cylinder bores.
IH sourced AMC 401 and 232 I6 in mid 70's light lines.