A cylinder head for modern street-strip use

If you were engaged in a conversation with a barmaid and she asked you to illustrate differing valve angles and to explain their relevance in simple terms, you might be challenged.

So here’s how it’s done. In addition we depict the cylinder head’s short-turn radius and describe its merits, identify the deck thicknesses and indicate its benefits, and characterize the difference between a standard port and a raised port. Free beers all round please!


Valve angles: 

These cutaways provide an invaluable insight into the evolution of Ford Windsor cylinder heads, particularly the induction tracts. At the top a high performance Ford cast-iron GT 40 cross-section is depicted; in the middle the induction section of a high quality 225cc aftermarket cylinder head; and at the bottom Kaase’s innovative P-38.

The intake (and exhaust) valve angles of the top and middle examples are inclined to 20 degrees from the deck face whereas the intake valve of the P-38, in contrast, adopts a much reduced angle of 8.5 degrees. Its exhaust valve is set at 10 degrees. Thus all valve tips are inclined inward toward the induction system.

However, unlike the top two, the P-38 additionally adopts a cant angle: intake 4.5 degrees and exhaust 4 degrees. This means the tip of the valves also leans either fore or aft (frontward or rearward). Read More…