Tracking you need to wait until the tear down, that's fine. Might search through NAPA on line. I've seen bearings and rings and by size in one of my saved Datsun vehicles. You will have to put in each model by each single year as NAPA has yet to figure out that an E-1 motor in a 1962 PL-320 is the same E-1 engine in a 1965 410. So they may list a particular part that works on numerous Datsun for one specific model for a single year, you just have to find the model and year for that specific part number.
Example is the Hitachi distributor. NAPA only lists the Echlin distributor for a 1962 320, period. However, we all know this same part works on many Datsun models with an E-1 engine with the Hitachi distributor.
Here's a link for compatible internal engine parts, no idea how I came across it, nor have I figured out how to find the homepage. So lots of Sprite/Midget, other MG and Datsun stuff works; pistons, rings, bearing, thrust washers etc. Just scroll down a little 'til you see 'E-1'
So you can compare the information from this website to the parts catalog for Victoria British or Moss Motors and order the correct part with the correct specifications you need.
Cam, yeah, I don't know if a 1098cc cam from the BMC A motor, Sprite/Midget, will work or not as the E-1 is a copy of this motor. Nissan just made the E-1 a little bigger at 1189cc. I also do not know is what else Nissan changed. I know the E-1 has a six bolt flywheel while the Sprite/Midget only has 4. I have also notice other subtle difference in the BMC A motor and the E-1 through trial and error.