Ok I have searched enough posts about flushing the system and none of them discuss changing the hoses, so here goes. When I remove the lower radiator hose from the truck won't coolant from the block drain?

 

Yes, the majority does. There aren't any drains in the block so that's the best it's gonna get. I usually don't change the factory hoses, but I usually pop the lower off for draining, then I disconnect a heater hose to help bleed the air when refilling.

 

Yes, but the same results can be achieved in a less messier fashion by opening the drain petcock. If you want to drain the most out of the block, remove the hose off of the vertical pipe coming out of the top of the head towards the left rear of the block.