I am messing with a 212 with my students. I cant buy anything for it so we going to make everything (air filter, exhaust ect.) and see how well we can make it run. We removed the gov and got it running pretty good all stock. Then we built an air filter setup and eliminated the air box and the power just fell off. What size should I drill the main out to? What size should I try after I do the exhaust? Anything else I can do to it to try and make power? I have the students mapping all the dyno runs to see what works and what doesnt. Thanks.