Stock gasket goes up to 69.mm.I just rebuilt my top end to 69.mm i used the stockIt has no overlay when on.I can send you an old ome  head gasket.You wouldnt  be able to run it or anything,But you can put it on your jug to see if their is any overlay. If you want.I talk to my local suzuki shop part guy.When i rebuilt this to make sure that i wouldnt  run into this problem.I knew the blaster took different headgasket for their  bore  size .So I wanted to make sure of this when i did my topend. Their isnt a better head gasket then ome.May be aftermarket kits are size like that but the ome isnt. You cant run a 70mm headgasket the largest bore size for the lt250r is 69mm unless you get a larger sleeve which contains machine work to do that.I will send you one in the mail if you want to check it.I went from .40 which is a 68mm to a .50 which is 68.25 to .80 which is 69mm. I used oem head gaskets on all three bore sizes. Th ome will work fine trust me.