Holley PART# 556-115 is a good way to get accurate timing on your small block Ford. It uses a 35 tooth (36-1) trigger wheel and a hall effect sensor.
If you follow Holley’s instructions you will end up with several issues:
- The crank trigger will hit your water pump
- The pulleys will be moved outward requiring all accessories to be moved out as well.
- The pulleys will not rest on the spacer hub, with the potential for it to wobble.
With some machining all three can be avoided.
The crank wheel also needs to be machined. There is a lip on the outside which will keep the wheel from sliding all the way on to the spacer. After the lip is removed it will fit flush against the spacer as shown.
The water pump needs to have some material removed so the wheel won’t hit it. I removed much more than this on an old pump and there was no problem hitting a water passage. It would clear fine with less material removed than shown here.