The performance of the Laurel-Roof antique performance cam is legendary. Although examples of this cam probably exist, the only information available to the author is the published lift and opening and closing angles.¹ A design which replicates these parameters is presented in Table 4 and Figs. 8 through 11. In order to achieve the higher lift while maintaining a short duration, the ramp velocity and maximum acceleration rates must be larger than for the improved stock cam. The designed ramp velocity is less than that for a stock cam running with a valve lash of 0.020. Although the acceleration rate is relatively large, it is difficult to reduce this value for a cam with so much lift and so little duration. There is a tradeoff between the ramp velocity and acceleration rate. Increasing the ramp velocity by 10% would reduce the maximum acceleration by about 15%. Increasing the size of the base circle would also reduce the maximum acceleration, but since this cam is already larger than a Model A cam, making it even larger might not be advisable. For the exhaust lobe, the dimension R_b + L_max = 0.777 in. is 0.090 inches larger than the holes in the block, so notches of this depth will be required. In this design, the maximum velocity was restricted to 0.0093 in/deg (0.535 lifter radius), so that 1 1/8 inch diameter lifters may be used.

Table 4

Laurel-Roof Camshaft Specifications

Intake Duration and Ramp Velocity

Exhaust Duration and Ramp Velocity