Cylinder Head Porting

We port cylinder heads with the following features:

The intake ports are opened up from 33 to 36 mm for an increase in port volume of 19%.

The exhaust ports are opened up from 30 to 33 mm.

The valves are unshrouded. The intake valve seats are blended into the roof of the combustion chamber.

The valve seats receive a three angle finish. The '90 - '92 intake valves are back-cut. '93 - '95 valves were back-cut at the factory. '90 cylinder heads are upgraded with exhaust valve stem seals.

 The camshafts are timed to I114/E110 +/- .5 degree.

The dyno chart shows the incremental power increase from the addition of cylinder head porting on an engine with top end porting. The subject engine is a '93 that also has headers. Note that low speed torque is maintained.