70 Z28 LT-1 Cam questions

[Kurt S]

I believe this post-script is being added to the article:

Note:

This progressive technique will ensure that ANY solid-lifter cam has the lifter for the valve to be adjusted on the base circle of the cam, but the actual lash dimension will vary depending on the height and length of the clearance ramps and the TRUE ratio of the rocker arms. The only way to determine that is to set up two dial indicators (one on the pushrod end of the rocker and the other on the valve spring retainer) and take readings on both in one-degree (crankshaft) increments for 720* of crank rotation, to develop a crank angle/cam lift diagram.

The measurements have been done for the "30-30" cam with stock stamped rockers, but for any other cam and rockers, the same thing must be done; we know from our work to date that the small-block stock stamped rocker ratio is 1.37:1 at initial contact and peaks at 1.44:1 at full lift (vs. a spec of 1.5:1), but we haven't measured a big-block. The BB nominal ratio is 1.7:1, but we don't know what it REALLY is either at initial contact or at full lift.