The mono block might work but mainly depends on porting it would need to be looked at and degreed in if it has been ported to far its not gonna be trail friendly.. next issue would be the spacer plate idea dont think that will work. Also the fmf is not going to be a good pipe for that setup.. look at porting a good set of stock cyl or a serval cyl... and you cant bore a stock cyl to 68 unless you resleeve it which imo is more money than its worth.