The small metal angle is the gauge to set the gap between the flywheel and the sensor.Just use it like a feeler gauge to set the gap between flywheel and sensor, tighten down sensor then take out gage and keep it somewhere for the next time you need it.The plastic block is an extra carb spacer probably the old style, you can use it or the better one that comes on the engine installed,the difference is I believe is one gives a better carb angle so you can hook up the throttle servo easier.Also I was able to use the original carb linkage by just putting a ball link on the metal arm instead of cutting off the linkage and putting on the plastic one that they suggest in the instructions...Well it was pretty easy and you will have a great motor when you are done...