Quote:
Originally Posted by motox2k  i have not used plastic, i undertstand that you only use this if you have made them too large and need to reduce.
any way, all i have done is match the inlet and exhaust port to the manifold.
inlet 
exhaust  |
the guys who get maximum horsepower use plastic to change the angle of the port to get a better angle to the valve, the guy who got 19.6 hp on the wheel didnt make the intake bigger than 27mm but changed the angle... is there anyone in usa that has as much power in his chinese engine???
on the heads i ported i carved out material around the valve to make it look like a sharkfin, then it splits the air and go around the valve instead of straight over it, this has made a huge different in power.. we have tried on taking away more material, but the biggest gains we got from just changing the shape.