So i just recently replaces the stock head with a gx160 head. I transferred everything over and now it wont start. It set valve lash to .003 on both intake and exaust. I also rejetted carb to .036 and a gx140 emilsion tube. It was running with carb adjustments before changing head. I have an autolite nascar plug and open header. If i try pulling it, it definitely has copression. It just doesnt start. White smoke comes out of exaust when trying to start. It also sometimes pops but never starts. Please help very fristrated. Thanks!