SOTP Vintage Series
Main Motorcycle: T140 E
Join Date: Jun 2009
Location: Reading Berks UK
Other Motorcycle: 56 Plunger Tatty Cub
Extra Motorcycle: CZ winter bike
It all depends on the laws concerning registration where you are but,
as GPZ says, cutting up a good bike is a bit of a waste, but at least you'll have a set of matching bits. A complete 68 is regarded as a good bike. If going that route, don't cut anything, bolt on and replace and keep the original bits. Bobbing only devalues a complete bike, so keeping the bits is a means of retaining the value.
Most Triumph engines are a common fixing inbetween certain series ( which are pretty big)
You can buy a factory metalworks frame - either a bolt on hardtail for pre-OIF frames or a complete frame.