What can you tell me from this engine number....?


Well-Known Member
I ran the blue car with a cylinder capacity of 3500 on the V5C long after it was changed to 4600, it was only after someone was interested in taking the car did I change it, so the new owner was correctly registered.
I followed these rules, which do not mention tax or MOT exemption, and the change went through smoothly.

Change vehicle details on a V5C registration certificate (log book)

MOT exemption is not lost with a capacity change as it is allowable, and not a substantial change. I always MOT'd the car, but I also had the choice not to as it complied with the current exemption legistlation.

Its academic now as I no longer own it. I was merely pointing out the pitfalls of being too open and honest when dealing with the Welsh.


Staff member
Fosseway four pots, 5 speed box, jag diff with LSD, uprated suspension, all considered non substantial.

Sparky did have the correct engine number on the V5C when I bought it, and the correct engine capacity, so I haven't had to deal with the DVLA as yet, except to change him to historic class.
What you have to avoid in these circumstances with an engine number change is opening up a very unpleasant can of worms by notifying the rego dept of a change,
This engine (if sound for rebuild) will be going into my Cortina - so there's a bunch of paperwork to do anyway, but changing from one engine# (as long as they're the same type) to another is a simple form here. The engine is really filthy inside and now I have the intake off I can see that the cam is (to my untrained eye) pretty worn, so I'm going to pull the engine down. My main concern is rot in the waterways...the heads look clean enough in that department but there's evidence of corrosion in the heater hoses, so who knows what I'll find.....