Five models of the 360/40 were offered.<ref name="mod40-func-char">{{cite book|url=http://www.bitsavers.org/pdf/ibm/360/funcCharfunctional_characteristics/A22-6881-2_360-40_funcChar.pdf|title=IBM System/360 Model 40 Functional Characteristics|id=A22-6881-2|date=August 1971}}</ref> The D40, E40, F40, G40 and H40 were configured with 16K, 32K, 64K, 128K and 256K of [[Magnetic-core memory|core memory]] and correspondingly 16, 32, 64, 128 and 128 <ref group='NB'>not a typo: the physical limit seemed to be 224; see p. 17 of the Model 30 Functional Characteristics</ref> multiplexer subchannels.<ref name="mod40-func-char"/>
The H40 occupied "more floor space than the other models."<ref name="mod40-func-char"/>{{rp|p.5}}
