Using low or nil road tax engine - how do DVLA treat ?

[Compo_Simmonite]

A neighbour has just bought a new car that is nil road tax. My cars are both low road tax bands. It's go me wondering how DVLA treat kits built using an engine out of such a vehicle.
Do they simply still work on the under or over 1499cc rule or do they rate it based on the engine donors rate ?
I'm refering to just the engine and management system out of a donor and not the who running gear so would expect Q reg applicable after BIVA.

Thanks.

Paul h

[Steve_D]

It would just be rated on the CC.
The emissions band is only relevant to that engine in its car at the time of type approval.
It would be a Q plate unless you had used enough other items from the donor vehicle.

Steve

[Compo_Simmonite]

Thanks for clarifying.

Paul H