Hello

Is there any way to identify if its an 914/6 gearbox or a regular 914 gearbox??

Which would be the main differences??

Thanks for your help

serial number and linkage in the end cap.
Serial # is a 75xyyyy where x is the year digit 0, 1, 2 and type # is 914/01 applies to five speed as opposed to the very rare Sportomatic
bottom; notice no long cast extension for gearshift connection
Click to view attachment
side; notice pivot on intermediate plate for throttle
Click to view attachment

The numbers are located here rather than on the spine.

Will look for the numbers thanks for your help, regarding the gearbox are they any different or just the same gearbox with different numbers??

This is my car kardex currently restoring

Click to view attachment

The parts are a bit different. The main casting may be the same as 911 transmission from the same year, but different from the 914/4. You can see a protrusion on right side of case at the bottom of the bell housing that is not present on the 914/4. The intermediate plate is drilled for a pin acting as a shaft for throttle pivot. The rear casting is unique to 914/6

The boss in the intermediate plate for the throttle bell crank is present on many tail shifters, just not drilled. The tail cone is unique and not the same as a tail shift 914/4. The gears will be different from a 914/4 as well.

Stock 914/4 is A, F, N, V, ZD
Stock 914/6 is A, GA, O, V, ZA

Sometimes, the holes in the top of the bell housing are round (early model 911, 914/6, some earlier 914/4) instead of square (later models).

Your transmission # is 7502662, and is a /6 box.

Cool piece of history.

shift linkage on the end of transmission looks like the top picture
and the end of the shift rod looks like the bottom picture.

Minus dirt and grease of course.

Click to view attachment

the shift rod under the car is different as well.

The serial number is on the spine of the early 1970 914/6 transmissions, the change occurred somewhere between car 300 and 400

Your transmission was built using the same casting as for the 1970-71 911 and the part number on the casting should be 911xxxxx. The casting differences Porsche made for the 911 are more reinforcing ribs inside the bellhousing, the tab on the outside of the bellhousing used to hold the 911 pull clutch cable and the serial number pad on the bottom.
The machining differences between the cases used for the 911 and 914/6 were the different locations for the vent on the top of the case and the location for clutch fork pivot inside the bellhousing. For the cases used for 911s, a steel reinforcement strip was installed inside the differential carrier to take the force of the pull clutch.
I have seen two 914/4 transmissions built with 911 cases. Probably done to use extra castings that were not needed for 911 production.