After getting schooled on BSA part numbers blush
I have a question on rocker arms. My bike was running
when I bought it and tore it down. The rocker arms are
different part numbers than what is in the BSA parts
list manual and no issues with that now that I know
more about BSA part numbers.

My question on rocker arms is that my rocker arms
all have MF A4 or A3 or A2 on them after the part
number. Is that like a revision number or what?

Also I bought an intake rocker arm that was suppose
to be 68-0147 (the same number as listed in the parts
list manual for the left intake rocker arm). What I got
was a rocker arm part number 68-0150 but it had
no MF stamped after it. The left intake rocker arm
I have is stamped 68-0150 MF4. The strange thing
is the one I bought the length of the arms are
shorter by a good quarter inch??! Both are stamped
68-0150? Anyone know why they are not the same
size? Need more expert help on this. Shouldn't
both be the same size? The seller (besides saying
the rocker was a 68-0147...had a tag on it in
the picture) said it was for all A65's. Is this an earlier
A65 rocker arm and not for my 1971?