Exhaust port question

[hotrodaj_2]

What does raising the exhaust 1mm do. I have heard of a mild change of lowering 1mm but a friend raised 1mm. Wondering what that does to engine.

 

[brandoz28]

in short it changes the port timing

 

[hotrodaj_2]

I understand that, was wanting to know if it gave better top end, bottom end, both or wont feel change. I might buy the cylinder from him and didnt want to buy a messed up piece.

 

[Wildcard2]

It will add top end at the expense of some low to mid power. If the port roof is too flat or the port is too wide it will cause premature ring failure. The shape of the roof should be rounded and even from left to right to promote proper guiding of the rings. Also be sure it has a good chamfer on the lip of the port to prevent the rings from snagging. Without exact dimensions I couldn't tell you what exact pipe it is cut for or the expected power delivery.

-Brandon

 

[hotrodaj_2]

Thanks, that's what I was wanting to know. Wildcard2, you have a great reputation on this site so the info you just gave I can trust to be right. Gonna get a smoke'n deal on a cylinder, Thanks