90/S2a Hyrbid

I am not sure if this is the right forum so if not i apologise.

I have a 1965 S2a V8 which sadly is a little worse for where. Its MOT'd but wont pass another with the bulkhead and chassis resembling a teabag.

I was thinking of possibly moving it over to a 90 hybrid with a brand new 90" galvanised chassis, coil suspension and 90 body but retaining the engine gearbox and axles from the 88".

If i do this and transfer the tax free chassis number over to the new chassis would my 90 looking hybrid still retain the 1965 reg and tax free status?

No

Ok,

So is there anyway a hybrid can retain the reg?

If not how come i see old registered 90's? (i drive past an old N reg(74?) 110 offroader everyday and it is most certainly not a modded 109")

You need to check with the DVLA. When you modify or restore these vehicles you amass various points depending on what you do. Once you reach a certain amount then you need to re-register the vehicle.
A chassis change is worth more points than an engine change but I'm not sure how its all worked out.
If you are using a donor 90 then chances are you will be able to retain the 90 plate but not your tax exempt one.
There is always the option of not telling anybody but if you come to the notice of plod then you'll have some serious explaining to do.

There are lots of 109's on 110 chassis and running gear plenty at L2b this year