I have a 1986 K5 Military blazer with the 6.2 in it..It starts perfect when it is cold it starts perfect when it is hot....but if you let it sit for 20mins to an hour when it is warm it will not start until you put a small squirt of starting fluid in the breather then starts up perfect and runs great..everything is all original except the fuel filter the gu I got it from had it for 15 years and has always had this problem but when he first got it the fuel filter housing was cracked and leaking fluid so he removed old housing filter and all and threw it in the trash and put a small inline filter on it like what would be on a gasser..this is the only thing that is different from factory would this cause the warm starting problem.

 

hard starting when its hot could be related to a worn out injection pump that has a worn out head and rotor and could be beyond repair.

You can check for air leaks too if you pull the return line from the IP and replace it with a clear hose, then you can watch for any bubbles made showing there is an air leak in the supply