. . . .
SPL311 Transmission Parts from Rallye Enterprises,
are two types of control arms used on the 1600 tailshaft
housings. The difference is in the length of the part
where it is held in place on the transmission tail
housing. The early type on the left; 1.25 inches long;
was installed up to approximately SPL311 09431. After 45
years of swapping transmissions; your car could have
either on it. The later type; 1.75 inches long; did away
with the spring and washer arrangement and opted for a
longer piece with more support from the inner bushing and
an increased resistance to breakage. This is the only one
available new and replaces both types. If you need the
short one you would typically either have to go with a
used one or swap in a different transmission tail housing
to use the improved version.