New injectors what cup to use???

So installed new injectors in the 1984 international eagle big cam 350 turned up 400. The injectors were supplied by the last owner, but the truck did not run correct acted like it was dumping water down through the cups and was putting too much diesel to the motor.
I eventually had the truck towed to my house cause I didn’t like the way it ran. I want to pull the injectors back out, pull their heads and replace the cups. What material do I use and what cup do I use please? They make cups in different materials just want to use the correct ones.

 

Pressurize the cooling system
With air im assuming
The old injectors were junk and there was water in the oil

 

Antifreeze it appeared
No rad tester yet
A lot of water

 

Oh, not worried about pulling the heads soda. Speak, more worried about calling the cops and replacing with new ones sounds like it’s a bit of a process.

 

I don’t like voice text

 

That should say I’m not really worried about pulling the heads as much as I am pulling the old cups and replacing with new ones it sounds like it’s a bit of a process