Like Peter said...a degree wheel is the most acurate. When I did my TR the plan was to use the engine builder's marks on the cams/caps as my guide. During this time I consulted other enthusiasts on "other" messege boards and was given tons of conflicting "advice" on what the proper or best technique was. Many said not to trust the builder's marks and use a degree wheel. So I did, but it wasn't totally necessary because when I had everything set, the builder's marks lined up perfectly. Peter is also quite correct in that the marks can be slightly off, but not enough to worry about. Just for fun I measured the degrees from one edge of the mark to the other....but still keeping them overlapping, and it amounted to just over 1 degree of crankshaft rotation. These overhead cam engines are quite forgiving and you can be off by 3 degrees and still run fine. Another difficult issue is setting up the dial indicator parallel to the shim bucket travel. I had to make a special offset indicator point, and a plate to mount the indicator to the head at the proper position. But once done it's kinda fun dialing everything in. You have to check valve operation at 0.5mm clearance. Rather than swapping shims into the bucket to get this clearance, simply install another shim to take up all slack, then "zero" the indicator on the shim bucket when the cam lobe is 180 degrees away or pointing outwards from the bucket, and then read the degrees once the indicator moves by the magic 0.5mm or .020" of an inch. Lastly if you do time the cams with a wheel, be sure you use the correct spec.s for your car, don't use Euro spec.s for a U.S. car, etc. Sorry to ramble on here......just wanted to share my experiences.