215mm - 225mm clutch/flywheels both need their mating starters correct? or are they interchangable?

 

pretty sure ALL flywheels non turbo are the same, and that is what the starter actually engages on. (dunno about aftermarket flywheels, assuming same also)

therefore you should be able to use any 12A strrter

 

yes all non turbo from 83-92 are the same thats the (225mm)
all 12'a through 82. use 215mm.

 

nah, you can mix-match starters on all non-turbo.

 

Correct. '74-'92 can technically interchange even though they look quite physically different.

Try this combo on for size: '74 bellhousing, S4 NA starter, RB light steel flywheel. I onlyh needed to trim a little bit of the casting flash so the starter snout would more easily fit since it is very slightly fatter than the earlier type. Oh and I had to use the FC longer starter through-bolt as they have a through-hole unlike '85 and older which have a threaded hole and slightly shorter long bolt. The short bolt is the same (or at least I got away with using my '85 and older short bolt).

The biggest difference, besides the couple pounds of weight difference, is the way it sounds. FC starters sound like a stuck pig.

 

awesome

 

except the all N/A RX-7 trannies dont come with removeable bellhousing.

 

That's fine because there is no casting flash to trim in RX-7 bellhousings. Just bolt in the FC starter and go.