Head Porting

Whitehead Performance N42


N42 Head ported by Whitehead Performance in Ontario


Un-shrouded and polished combustion chamber. Bowls are both very polished


Exhaust Port: note the shortened exhaust valve guide and reduced pile of aluminum. An end mill from a milling machine on a drill press can do that.


Exhaust port detail. Median is bowed around water passages. Look at the coarse machine lines


Intake Port and valve guide. It has been shortend or a shorter guide installed. As well, the aluminum build-up around the guide is nearly gone!


Intake port and short side radius. Not so polished near the roof

 

Rebello N42


Rebello Porting Job (Intake) Very smooth but no changes to valve stem, just the aluminum mountain around it is reduced and blended.


Rebello Porting Job (Intake)


Rebello Porting Job (Intake)

Porting N42 from a Japanese Site

 

Cross Section of an N42



L28 Cut-Away exhaust port and cooling passages

 


L28 Cut-Away exhaust port and cooling passages


L28 Cut-Away intake port and cooling passages


L28 Cut-Away intake port and cooling passages. Boring in with a 40mm hole cutter at 15 should accomplish the above. However no details of side water passages are shown.

Port Details


Intake Before & After


Exhaust Before & After (look at the base of the valve seat where it has been blended with the port wall.
 


Valve Job

E88 Head on big bore


Polished and Ported E88 (note the bronze intake valve seats)


Polished and Ported E88. Very Smooth Chambers and relieved valves.
 


 

 

 

Hit Counter