s13 ka24de vs s14 ka24de

s13 ka24de vs s14 ka24de
I’m new to Nissan’s. i bought myself a nice s13 hatch. turns out the ka24de in it is leaking from the front main seal…i was gonna get a whole new front timing cover that comes along with the seal and oil pump…felt i might as well…the best priced one i found tho was for a ka24de for an s14(95-98 models is what it says)
Which makes me wonder…is there a difference between the two?
between the dohc s13 and s14 ka’s?
if so, what are they?
and if not…why sell these parts specifically for those years?
just curious…