Technical Information:
Hex Size (mm): 16
5/8” in the old money
For most jobs on our cars a 3/8” drive socket set would be best….. not as bulky and will give you a bit more wriggle room in the darker cramped nether regions of our engine bays.
In fact a combination 1/4” and 3/8” drive set would be best
Thanks for the info everybody.
As for the socket drive size, I've had my socket set (which is a high-quality AF/Metric set) since I was about 18 and running an Austin A35, so over 50 years. It's 1/2". My torque wrenches are both 1/2" too. I also have a half-decent 1/4" set which I bought when I first got my TF about 7 years ago. I actually use that set a lot more. If I didn't already have the 1/2" stuff, I'd get 3/8" now.