Land Rover Series I, II, III Club - Forum

Hello all.
I'm after some advice regarding my land rover series 3 1973, which was originally a 2.25 petrol.
It has been converted to a 3.5 rover V8. The engine originates from a 1976 rover P6 according to the engine number.
My current V5 still has 2225cc on it. How do I go about changing it to a 3500? I've read all works need to be verified by a garage? I don't want yo loose the registration or historic tax status.
Any advice appreciated.
Andy

There's a section in the V5C to do this sort of thing. Don't forget to notify your insurance company.
Just send it off. It's a Rover engine after all .