Yeah, go for it!!
A few yamaha mechanics once told me the blaster frame was adequate to take the torque developed by the YZ250 engine.. But we discussed finding the model of YZ that would fit the frame best with the least mods. Verdict was, Find an older YZ with the frame, electrics and the engine that barely runs.. sell all the rest, but keep the frame so you can cut off the engine mounts and weld em onto the blaster frame.. Then do a rebuild. Mounting the rads is tricky, but you can get away with using more smaller rads if you can get them used. it just makes it easier to find space for.