To make sure that your chain is correct and that your camshaft and crankshaft are in sync you should check on the following:
When the mark on your flywheel is lined up with top dead centre, both No 1 and No 4 piston are at the top.
Your rotor points at No 1 cable on your dizzy cap, but when the rotor points to No 4 cable (then it will be 180 degrees out).
Take off your rocker cover and watch how the rockers move.
After lining up the flywheel mark, turn the flywheel clockwise. As soon as you start to rotate it, No. 7 valve, which is the inlet valve on No 4 cylinder will start to open.
If No. 2 inlet valve on cylinder number 1 starts to open, then you are 180 degrees out.
Remember when you set your dizzy/points that the shaft/rotor rotates clockwise, so the felt tip of the points should be before the lobe on the shaft.
To explain it better using a clock face, if the lobe is at 2, then the felt tip must be on the 3 side (not the 1 side)