I can understand your desire to use a SBC in the Datsun, and even the desire just to hear the "song" a high RPM Chevy V8 would make.
I also like some suggestions about getting an old NASCAR engine.
But I also think the suggestion about using other engines, possibly ones that are more current, and come with the ability to run the higher RPM, from the factory, because of more than two valves per cylinder, variable valve timing, and fuel injection. Honestly, the Chevy V8, although a good engine has been over done. I am sure many of us have been to car shows, where it is a matter of this. "Oh, look, another 32 coupe with a Chevy V8".
But it is your car, not mine. Good luck with the project.
Now, if I could figure out how to get that Ford FE 428 into one of my Datsun 521 trucks, in the shed. And not just put it in the pickup bed.