If you want any help, Id be happy to have a look under your car and see whats capable of fitting in there.
I dont remember what the 4spd in my 140j parts car was like.
Dan could tell us and post a pic???
I dont have any L-series gearboxs these days sorry.
R30 stumpy 5spd are the shortcase type, or you can go for a 160j sss 63a dogleg box.
180b sss has the dogleg longcase box.
910 bluebird has the standard h-pattern longcase box.
There are probly other options too.
72 Datsun 1200 Wagon
86 Toyota AE85 Trueno 4AGE ITB