I'm considerin using blocks next track season for my 800 races.
Here are my reasons.
I average about 57 secs per lap in the 800. My GF runs a 400 in about 62 sec and she uses blcoks for the 400. So since 57<62, it follows that blocks will help me in 800.
If I ever get down to 61-62 per lap in the 1600m I may use blocks for the 1600m as well.