I believe E body spindles are the same as 73 and up A, are they not?
FMJ is the same as 73 and up B, again IIRC.
The whole point on the FMJ to me was-
I've seen exactly two 73 and up A body cars at the U pull yards since the late 1990's.
(I go to six yards in three counties every year if not more frequently)
I've seen more than two dozen F and M body cars in that same time frame (and two J's).
With a few late 75 and up B cars showing up as well.
If the handling differences are negligible, then the supply difference becomes a non-issue.
E-berg ragged the FMJ part pretty hard in his article.
BigBlockDart refuted it with tangible evidence, and I believe them.
Case closed for me.