Originally posted by SNACKPACK
hi adsl
what you can do is blueprint the motor. make sure that when the piston is at BDC [bottom dead centre] the top of the piston is level with the bottome of the exhaust port. if the top of the piston comes down further than the bottom of the exhaust port, make the bottom of the exhaust port longer until the top of the piston and the bottom of the exhaust port are flush.
i hope this helps. 
If piston is not in flash, how does it affect the engyne performance? What is happening there when it is not in flash?
Just recently been proven, that if piston goes further down then bottom line of exhaust port works better. How much further-0.5-0.6 mm. anything else will not work ( 12 Novas based engines). The same with boster and transfer, but numbers are different.