I don't understand a few things. One is how planes fly, and the other is why Chrysler would have an exhaust manifold stud enter a
water jacket in the head. I know this is normal and have come across it many times. I just repaired a leak that could have looked like a head gasket but wasn't.

 

It what it is!!!! Lol
the Mopar would!!!

 

Why are the studs also undersized? Their 5/16 instead of 3/8...

 

I don't ever recall removing broken studs on Mopar V8s. I certainly recall plenty of leaking studs. That job doesn't look like a fun one, but it looks like you're on the home stretch. Studs are meant to be moderately tightened gaining its fastening strength by using all the threads compared to a bolt that gains its strength mostly where the tip tightens into the hole. I'm sure Chrysler had a thought-out plan but I'm still searching for it.

 

Removing broken studs on any installed V8 is a pain, GM and Ford have problems with manifold bolts breaking and if you think your Mopar is bad try doing the same job on a newer GM pickup. Aluminum head junk hardware and no room to work on it. You finally get the bolt loose and the electrolysis on the end of the bolt reams the threads out in the head.
Fun day

 

A friend of mine who was an engineer said "it makes sense to have coolant touch the studs. He said by doing that it reduces the amount of expansion and contraction that may crack the manifold. Did Chrysler really think that much back in the day?