You can use a ae86 intake if ii want to go the easy route. Since it has a flapper door maf I wouldn't do a "cold air" I would just do a filter and adapter they can be had on ebAy for less then 20 for the super cheap ones. I would buy an adapter and then a rtec filter they are nice yet affordable. Again both found on eBay. Replacing the rubber tube helps reduce air turbulence as well. Something should be a available or just get some 3" bends from eBay and cut and couple your intake together.
I have a Metric S&!T ton of Datsun/Toyota parts pre 82 let me know if you need anything,
73 rb25 240z, body Bracing, cage, paint in progress.
78 Cressida Body, Paint, and 2jzgte in progress.