Hi, as I understand it, if your car contains enough of certain bits of a donor car it is allowed to keep the registration. Does his mean that if my donor car is registered in 1970, then my kit car would be tax exempt?

No it wont be tax exempt. My donor car was a 1968 G reg. i got an age related plate but the car is registered as first used in 2004.
The good side is i wont need an MOT for three years.
Paul.

OK, thanks.
On a similar note, how stringent will the emissions tests (SVA? and MOT?) be on old donor car kit car be compared to say a two year old car? Or are they the same no matter what?

As far as i know, old donor engines only get a visual test at mot times where as new engines have to have a cat fitted to be able to pass mot !!
I think the cut off date for 'old engines' was 1995 ?
Jason

not sure thats right jason, but then im no expert. i think to be visable smoke test only it has to be very old, or Q plated. Post 95 will need the cat, before that they need to meet less stringent requirements, but gasses are still tested. mot place will know for sure.

A post '95 will need a cat and pass the emmissions at SVA, but will only be tested for visible smoke at mot if on a Q plate - silly really

As posted before.
Visable smoke only at MOT regardless of age or registration.
There are ideas about making Kit cars comply with production car emissions tests at MOT time but unlikely to be applied retrospectively when that happens.

John