Ganesh
I feel your pain brother. I went through this a few months ago trying to get my 235 timed/started. I did come on this site and used the search feature. Found some post by bolter "Pete52" that helped me out.
The problem I had was when I installed my distributor, the gears were off a tooth or two. I thought my distributor pointer was at number 1 but it was off slightly. I finally corrected that by using a screw driver to move the oil pump. After that the tang dropped in and I was at the correct position.
A second problem was at my first attempt to line to pointer to the ball I was 180 out. My number 6 was at TDC instead of number 1.
On my flywheel the ball comes just after the triangle. So when I triangle show up I just move my flywheel a few inches then the ball shows up. The ball is just a stamped circle.
I painted mine white with the pointer just as 49 floyd suggest.
heres a pic
flywheel ball pic This helped when using the timing light.
Heres a pic of the triangle
Triangle pic Like Curt B. stated since your using a 216 flywheel the mark may not work for you.
I have read on another forum the that mark should work for you if you have the early 235, but not the later High Pressure 235.
"The full pressure 235's are timed at a diffrent degree of advance than the 216s and early 235s. The 216 and the early 235 low pressure 235 used the same timing. The position of the timing mark on a late 235 flywheel would be in a diffrent location thant the others."
Good luck