I need some help with an old Dodge truck.

As far as the flattie goes, block will be full of scale/dirt/rust.
The core plugs are not real easy to find, brass are better. Behind water pump is a water distribution tube, you need to make sure its intact. I got my water pump from rock auto

p15-d24.com is a wealth of information.
I used vicsdodgegarage.com for parts. One man band, good to deal with.