It doesnt look like a part on my 74 Special (with a 365 gearbox) gear Iinkage, which is fundamentally the same as a 352 linkage I believe. The only part that bolts to the chassis is the gear lever, everything else bolts to the clutch housing or the selector shaft at the back of the gearbox.
I don't recognise the part from mine. Could it me a throttle/choke/clutch cable mounting that has been "improved/redesigned" by a previous owner?