So, if we had a Chevrolet 23-degree head with a maximum width of 7.625 inches and we desired to make a 1-degree change in valve angle (from 23 to 22), the formula would be: C = 0.0175 x 7.625 x 1C ...

Low valve angle heads in the 7- to 12-degree range with port heights of 1.250 inches or more are the most efficient designs possible today. Pro Stock heads are 9- to 10-degrees for a reason.

Head tube angle is best envisioned as an imaginary line that runs through the centre of the head tube, in profile. This is ...

JGM performed all of the required machine work on the head, including machining the valve seats to a 15/30/60-degree, three-angle valve job. A normal 45-degree, three-angle valve job employs 30/45 ...

With valve angles ranging from 12-18 degrees, air enters the intake ports at a straighter line-of-sight trajectory than with a 24-degree head. Consequently, spread-port heads will make more ...

Giro bases this claim on wind tunnel testing results and a formula that factors in 72 different yaw angles for a rider going 25 mph with a 30 degree head angle (the most common head angle whether ...