WD Big 4 engine and frame numbers  (iss 128)

Looking at the various lists available, it seems that there are gaps in the numbers known versus the numbers expected. One way to try to fill these gaps is by making an inventory of all existing numbers. This wil inevitably be an incomplete inventory (many bikes lost, not everybody responding etc) , but it will hopefully give some insight in the numbers. 

Norton used a rather confusing system to number frames and engines from the early start. Frames and engines were numbered at manufacture but there is no link between them, nor any prefix used. Hence, all pre war military Nortons had different i.e. "non matching" engine and frame numbers.
With the start of the purely military production the frame and engine numbers were matched and given a Big 4 model specific "S" prefix starting with S1000 around November 24th 1939.

Like with WD16H engines, also engines with an AS prefixed spare engines are found.  Norton did not make a distinction here to separate 16H and Big 4's. 

Dating the bikes based on the contract numbers is a tricky issue. Bikes made on a contract date in one year could very well have been delivered the next year. I added the most likely manufacturing year without pretending to know it exactly!

The only valid position for a Norton applied frame number is on the left hand front petrol tank frame lug casting. The engine number is found on the left top corner of the left crankcase half. Sidecar chassis number is found on top of the front lower sidecar to motorcycle fixing.  (See pictures below).

On (WD)16H´s I have found different casting numbers on head stock and saddle fixture. I'm wondering if this has happened with the BIG4's as well. If anyone has these numbers, please add them. Frame casting numbers are found at the left, aft side on the steering head, saddle casting number is found on the left-hand side below the saddle. 
Petrol tanks have individual numbers at the bottom, front forks have individual numbers at front lower cross brace (left hand side when viewed from the front).

If you want to help unravel the past, please send me your frame, engine and sidecar chassis numbers (and preferably the others as well).
If you want to have your bike on the website, send a picture.
I will only add bikes to the website after the owner has given his written consent unless it is a museum piece or publicly advertised for sale!

Note: In case a frame number is not known or  not applied by Norton, the engine number of the MC is "assumed" to be matching  and the MC added in the list accordingly.
Given

Rob