The idea is to put the No. 1 piston at TDC, install the distributor slightly advanced (like 15 degrees), and adjust the timing with the engine running. Or you can put the piston at 15 degrees BTDC on the compression stroke and point the rotor right at the No. 1 position on the cap. We prefer the second method provided we can see the timing pointer and it is indexed with numbers; some of them aren't. If you just have a big blob on the balancer that is marked with a big TDC, you get to use the first method.