heads yes
cam, no - as the block is not machined for roller lifters
if there are roller rockers, then yes (stock vortec heads do not have roller rockers)
The impeller (raw water pump) sits between the upper and lower. Since you have it apart, I would get a new pump assembly as well as inspect the splines of the 3 pieces of the vertical driveshaft (known failure point)
I would look at axalta coatings or the Dupont industrial line
You need an ecthing base primer followed by an epoxy sealing primer
I would do wet on wet
the 3.0 (181) is just a bored and stroked 2.5 (153)
nothing special about either of them. in fact, the 3.0 replaced the 2.5 in 1991 (yes, 31 years ago)
I normally drill two 1/8" holes, just off center of each other, then turn that into a slot. then drive a screw driver into the remainder of the plug and back out
it has been done. that is a huge expense and lots of work.
here is the thread from oops doing just the thing.
https://forums.iboats.com/threads/hull-extension-in-progress-with-pics.231766/
