wr450f bottom end with yzf top end?

[morgan_robles]

I'm new to dirt bikes so this is probably a bumb question but here it goes. I recently bent my valves on my 2003 wr and am deciding to just buy a new top end. Only problem is there hard to come by and are usually pricey, yzf top ends on the other hand are pretty cheap and all over ebay, is it possible to put a wr bottom end with a yzf top end??

[FORMA MOTO]

Yes

 

Don't know the best crossover years however.

[morgan_robles]

So it's not necessarily going to match with the same year yzf head?

[FORMA MOTO]

No there is no direct correlation some years.