Tread carefully, by example the 1979 and 1980 dt175's engines are identical. Just ig system is different. On the actual bike they changed the airbox amongst other small changes. Depending on model the main jet varies by up to 50 points, yes from a 130 to a 180.
All engines run at a certain fuel ratio, the fuel also acts to cool the piston crown, you can get brave and run a leaner fuel mixture, that will give more power with no changes but your pistons will run hotter, you will also be riding harder to use the performance compounding the effect. Ultimately you could be riding into an engine sieze, I have done it, many others too.