Need help identifying flywheel.
 

That looks like a series 1 flywheel

What year is your engine? Looks 83-85. What rotating assembly? There is a chance it's the wrong flywheel. That flywheel looks like an 81-82 but I don't have any 79-80 here to look at for comparison.

You really almost have to remove it to figure out exactly which flywheel you have. Mazdatrix has a page that show the various markings for each year.

Flywheels

Unless you back-dated that oil cooler, it's fairly safe to say that you have the wrong flywheel (based on the link TG Farrell posted above) from your photo. I see markings on the tension bolts, so recently built? By you? And like Jeff20B asked above, what rotating assembly?

If it is an 81-82 like I suspect, he will see about 225mm, but that is due to the actual friction surface he is measuring. This means he can probably install a 225mm disc. However he can't fit a 225mm pressure plate due to its step height which differs from a 215mm pressure plate, which is what he should be using on this flywheel.

https://cimg6.ibsrv.net/gimg/www.rx7...310ea11a67.jpg
https://cimg7.ibsrv.net/gimg/www.rx7...77e66cf5cd.jpg
Just FYI, 81 - 82 flywheels are compatible with 79 - 80. They fit together the same and are balanced to each others rotating assemblies. Difference is, the 81 -82's are about 7 lbs. lighter overall. Sounds like your engine needs a later flywheel to balance it out and fit up. The pic's are from an 81.

The rotating assembly is from an '83 and the rest of the build is from an '85 (irons, housings). I had this motor rebuilt recently but since I didn't have the '85 flywheel with me at the time, the builder had this one available to put on. So now that I have the original flywheel, is it okay to remove this one and replace? Would that affect any of the endplay of the engine?

I have a 225mm disk and a 215 mm pressure plate available, however the rotating assembly is off a '83. Is it alright to use this flywheel with said disk and pressure plate? I now have an '85 flywheel that I can use to replace, but I'm afraid of affecting something inside the assembled motor (ie pinching something or moving endplay).

Flywheel won't change your endplay. You can (and should) put the correct flywheel on the engine. My only question is did your builder use the front counterweight for the flywheel he installed or was it correct for the rotating assembly?

Rotors and e shaft are from an '83 as those were the only good ones I could source, counterweights and the rest of the motor are original from the '85.

You should be good then.

Whoa. Whoa. Wait ... I was only responding to your question about changing the flywheel. I'm not sure about the clutch question. I've been under the impression that the 215 plate will not work with the 225 flywheel, but I've never had to see for myself.