An alternate means of measuring...
An alternate means of measuring lobe lift uses this trick cam-checking tool you can get from Powerhouse or Crane Cams. It fits snuggly in the lifter bore and reads directly off the cam, eliminating the chance of misalignment when using a gauge extension.
The Easiet Method: Checking Lobe Centerline
There are two common ways to degree a cam. The easiest is the lobe centerline method. With this method you can find out if you've installed the cam correctly and, to a certain extent, check to see if the manufacturer's grind is correct. Without changing your degree wheel or pointer position, rotate the engine until you see no movement on the No. 1 intake lifter, pushrod, or rocker arm. Use the longest ratchet or breaker bar you can when turning the engine for smooth movements. Short ratchets lead to jerky motions and inaccurate readings. You'll want to install a 1-inch dial indicator reading off the No. 1 intake lobe of the cam (second lobe in from the front on the driver's side of the engine). If your engine is fully assembled, it's easiest to use a pushrod as an extension for your indicator (see photos).
You'll also need to use a solid lifter lubricated with engine oil only on the intake lobe; hydraulic lifters cannot be trusted to read correctly. Turn the crank clockwise until the indicator reaches maximum lobe lift. Zero the indicator at max lift point and rotate the engine clockwise two full revolutions to check that the gauge returns to zero. If it does not return to zero, check your indicator/pushrod alignment to be sure it is not binding. Starting at zero, reverse direction and rotate the engine counterclockwise slowly until the indicator passes 0.050. Stop around 0.090 (this step will eliminate any chance of timing chain slack affecting your readings) and switch direction to clockwise rotation. Slowly turn the crank clockwise, watching the indicator and stop when it reaches exactly 0.050.
Follow the instructions in...
Follow the instructions in the text to find true TDC then move the pointer or wheel to indicate it before degreeing the cam.
Write down the reading on the degree wheel, i.e. 64 degrees. Continue rotating clockwise until you see the dial indicator reach zero and start moving again towards 0.050. Slow down and stop exactly on 0.050. Write down this reading as well, i.e. 151 degrees. Add these two figures and divide the sum by two (64 + 151 = 215/2 = 107.5) This indicates your installed intake lobe centerline position. If this figure closely matches (+/- 1 degree) the intake lobe centerline indicated on the timing card that came with your cam (i.e. 108 degrees), it is installed correctly. If it came up higher, say at 112 degrees, you've installed the cam retarded (4 degrees in this case) or if the figure is lower, say 104, you've installed the cam 4 degrees advanced.
If your figures indicate that the cam is advanced or retarded and you have correctly aligned the marks on the timing gears showing the cam to be installed at "zero" or "straight up," then the cam was ground slightly off and you can correct its installed position a number of ways. The easiest is by repositioning the crank gear of an adjustable timing chain set. Or you can drill the cam gear's dowel-pin hole and install offset bushings to adjust cam position. Of course the easiest method is also the most expensive, but if you run a belt drive, you can quickly and repeatedly adjust the cam position at any time, without getting messy.
Erson's Pro degree wheel features a movable outer ring that's secured by four thumbscrews. It can be turned independently of the crank hub to align the wheel at TDC. The wheel can also be used to turn the engine by hand if it's installed during the build-up phase with only the No. 1 piston in the bore.