the problem is that the dt/wr 200 changed at some point.. the DT/WR200 from before the 90's has the same cases, and your blasters exhaust will even fit if you put the DT engine in your blaster frame because the cylinder angle is the same.
early in the 90's the DT engine changed (different cases and different cylinder inclination meant fitting it in a blaster and getting the exhaust plumbed was a beast of a job)
the cases used to be exactly the same, such that you could keep the blaster inner cases and put on the DT/WR200 outer cases and then it wouldnt need drilling.
One must also consider the gear ratios, which are different on the DT/WR200 engine.
Other than being liquid cooled, the other main benefit of the dt/wr engine was the provision of the electronically controlled power valve and the fact that it had WAY more power than a stock blaster motor as it was stock.
a lot of people that have the older sought after DT have it as a collectible, but if you look on ebay, you will find on occasion an old DT. that way you can get the carb, the electronics and the rad but will probably have to rebuild the engine their so old..
i always fancied putting a YZ250 engine in my blaster.. You?
theres a guy whose put a KTM460 two stroke in it.. thats gotta be fast...