250-500cc 250 to 300

If I got a smoking deal on a wr250 how much is it to convert to a 300? I assume the bottom ends are the same. Are the pipes the same? Just swap jugs and piston? You can swap the Ktm 250 to a 300 for under 900.

Well the pipes are not the same but from what I understand the 250 pipe works fine on the 300. The kit from husqvarna is 1500 but you can get it a bit cheaper. The 1500 includes the 300 buck stock 300 pipe. You can piece it together for much cheaper. About 900 without a pipe. Then if you really want you can buy an aftermarket pipe for 2 bills.