KA24e/de are nearly the same for the swap only real difference is the wiring.
One side note: This swap can come off as confusing and hard to understand.
One keynote I found was a video, this video helps with the wiring issues.
https://youtu.be/7DEQZRBq-Fc
FSM recommended to locate the one for the ka swap pulled (240sx s13 – s14)
NicoClub.com/fsm
A few guides in this will be the following, CS12 provided the most information for this topic but even that is a bit unclear to some.
KA Swap Guide:
http://club-s12.org/retro4/index.php?topic=29782.0
KA DOHC Swap guide:
http://club-s12.org/retro4/index.php?topic=21003.0
KA SOHC Swap guide:
http://club-s12.org/retro4/index.php?topic=25320.0
S12 to S13/S14 W71c transmission guide
note: mk2 models just need the transmission and the front half of the drive shaft and it will bolt up.
http://club-s12.org/retro4/index.php?topic=29974.0
some other key notes provided by NicoClub that can be helpful is the s13 SOHC to DOHC swap. Only the helpful part is the wiring.
http://www.nicoclub.com/archives/ka24e-to-ka24de-swap-step-by-step.html
//Printable pdf coming soon.