Going from memory and not counting the very limited 360/20, from the 8 bit internally 360/30 all the way to the 360/91 supercomputer you could run basically the same software. Which eventually solved a huge problem for IBM and the industry in general because not so much effort had been put into comparability in the early days, and IBM had two major lines of big computers, decimal ones for business and binary ones officially for science and engineering but by then often used by businesses.
Although stuff at the low end which somewhat like the 360/20 remained incomparable, the business 1401 series remained, also see the scientific 1130 which a lot of people including myself got their first start at programming on. It was a very clever design that used 360 technology to make an affordable system, for quite some time they'd put effort into that niche with the 650 and the CADET, Can't Add, Doesn't Even Try, a backronym from how they based it on a big block of core memory which they were very good at manufacturing by then vs. the drum as used in the 650, and and used that with tables etc. to avoid including an ALU.
And leaders of the effort going all the way up to Tom Watson Jr. made a catastrophic mistake in deciding virtual memory, which they called dynamic address translation (DAT) was a bad thing, which hardened so much the first models of the System/370 which used "monolithic" circuits, ICs, didn't have it (and they didn't do right by their customers who bought those first models).
The affordability of the 360 series and their ability to make so many but much less than initial demand rested on their avoiding too new at the time ICs and using automation to manufacture small boards logic boards on a ceramic substrate: https://en.wikipedia.org/wiki/Solid_Logic_Technology This was an era in which IBM still massively benefited from its electromechanical wizardry gained in the punched card data processing days.
This lost them the high end computer science community which I believe seriously harmed them in the long term, ultimately made what they now call IBM Z a niche product.