The 510 came with a F4W63 4spd standard transmission with syncromesh forward gears. It was characterized by a heavily ribbed aluminum central case and integral bell housing with a bolt on removable bottom pan with drain plug, a middle steel adapter plate containing the attached gears and an aluminum tail stock with driver's side speedometer. The only L series transmission to do so. It was approximately 26.3" long and considered a 'short tail' transmission. The same transmission was used in the '70-'72.5 521 truck, but had a flange output which has to be removed if used for swapping, and the '72.5-'73 620 truck, but without the flanged output. The F4W63 used a rubber mounted 'A' type shifter which was usually quite worn and sloppy and known as the infamous 'monkey motion' shifter. The wagon used a wider ratio gear set while the sedan, a closer one, with less RPM drop between shifts.
A popular 5spd swap was to install the transmission from a first generation 200sx (S-10)'77-'79. Though not a very tough transmission, and somewhat rare, it was adequate for the stock L16 motor of the 510. This 5 spd had a unique 'dog leg' shift pattern either loved or hated by owners. No alterations are needed.
If the 510 drive shaft is shortened, a Roadster 5spd can be used. This will require the removable bell housing to be replaced with an L series from an early 240/260 Z car or the Z car transmission itself. Quite rare but very tough transmission.
With a shortened drive shaft the 'long tail' FS5W71B 5spd from a '77-'79 620 truck OR the '77-'79 280Z car can be used. Both these transmissions have the same wide ratio gear sets. A 'close ratio' FS5W71B from the '80-'83 280ZX can also be used providing less RPM drops between shifts. All three have the same physical dimensions but may or may not have a neutral switch or hi gear switch in addition to the reverse light switch.