Factory EFI
Datsun made a factory EFI manifold. See EGI#Intake.
Buffalo
Buffalo made an aftermarket manifold for their ATV project, now since discontinued.
Danie van Vuuren supplied all the fuel injection components for the Buffalo ATV project. The intake manifold is custom made & high quality. Price about R1800.00 as of September 201 for the bare intake manifold. Danie can supply you a complete setup or just the bare manifold.
DCOE Conversion
Many EFI kits are available for a Weber DCOE carburetor manifold.
See EFI