Z28 Cam

[Brew14u]

I have a 1969 Z28 that I believe has its original motor based on engine code and partial VIN stampings.  I read the excellent CRG report 302ci Engine OEM Valvetrain Adjustment and wanted to adjust my valves.  Then it dawned on me that I really don't know whether it has the original cam and solid lifters.  Is there a way to determine if it has solid lifters short of pulling the intake?  Is there a way to determine whether it has the factory "30-30" solid-lifter cam (PN 3849346) short of seeing the part number?

[rszmjt]

You should pull the valve covers and WITHOUT adjusting them run the lash to see what it has rite now for lash. The stock cam is .030/.030, if its anywhere close you can make a decision and relash it at that. You could also use a dial indicator and measure the lobe lift at the pushrod, but you would have to remove 1 rocker, then multiply that by the rocker ratio to give you theoretical lift, Z cam is .485. You could also put the dial indicator on the retainer and that will tell you lift at valve.

Short of putting a degree wheel on it its hard to measure duration.

[Stingr69]

Good advice to measure lash now before you do anything.  Once you know where you are there...

A magnetic stand and a dial indicator on the tip of the intake pushrod would help establish the gross lobe lift of around .320"

If you can rotate the engine freely a few times with the dial indicator on the pushrod, you will actually see the very slow lifting movement on the dial for the first .020" of lobe lift.  The ramp lift speeds up real fast right after that.  If you can see it in the dial, you probably have the stock 302 cam.

I would lash it at .026"/.026" If the rocker arms are stock.

[Brew14u]

I appreciate the responses.  I usually try to start with the simplest solution, so measuring the current lash sounds like the way to go.  Thanks.