My mates looking to sell his Clio Cup 172 as the tax is going to be £400 a year soon! Hes looking at a bike powered car but wants to know how much tax they pay a year.
Cheers 
400 for a clio,that is madness…
Exactly - I think he said it’s in the top bracket for tax now though, its only a 2.0 16v & has to pay the same tax as all the 4x4’s etc
My Dax Rush is taxed as a 1300cc car . . . pre-2001 even though it’s a 2004 reg car, so this year i paid £120 tax 
http://www.direct.gov.uk/en/Motoring/OwningAVehicle/HowToTaxYourVehicle/DG_10012524
This shows all the vehicle tax rates.
Cheers! A bike engine in a car seems a bit of grey area when it comes to road tax pricing
Not really … it would be still classified as a car, and would be taxed according to the amount of CO2 produced.
Wait until you come to get it MoT’d ! Some newer V5C’s have the CO2 rating on them, some don’t, some older cars are visible smoke test only rather than a CAT test.
Best bet is to get a pre-2001 car which has a car engine, probably a pinto or x-flow or something reasonably cheap, make sure it’s visible smoke test only on the MoT and then swap the engine for a bike engine, or buy one where somebody has already done the swap.
That way you get the cheap tax and the MoT is basically a quick safety check, no emissions testing.
Or get a diesel. I changed my 1.6 to a 1.9 tdi a few months back and saved 50 quid already, and it reduces next year too.
My sister used to have a 1.4 diesel focus and paid £40 car tax, she had to change to a pre 2001 corsa and it’s gone up by over 100 quid.
So get a diesel with a small engine and save. Just don’t park the bike near it 