i was told that the head gasket would be a pain to replace and would be a lot easier to replace the whole engine

 

Well that is not true, head gasket is way easier to replace than the motor. But by your description, it sounded like it was driven for a while after the gasket blew and even overheated and now the oil PSI drops to nothing, so It may be a waste of time just doing the head gasket.

 

i do agree and with that many miles on the motor i would just do the swap if its just gonna cost u labor

 

head gaskets are not a hard job at all

but the loss of oil pressure isnt a good sign. check your oil. is there coolant in it?

Are you sure its not the combo of a leaking plenum and timing cover gasket?

 

Oil PSI gauge dropping could be bad sensor, My truck did the same while at stop lights Check gauges light would pop on too.
Changed the sensor and that took care of that.
That and head gasket would surely be easier than a swap.

 

how bad is it to replace a hg or 2?

 

id do the swap....after rebuilding the 318 out of the Jeep, punch it out some, high compression pistons, hotter cam, heads and an airgap

 

can i put a 5.9. in a 5.2 ram engine slot and what would i need to do to make this work?

 

This is exactly what was happening, could you please tell me where to locate the sensor to replace it?

 

Except Vteens didn't get driven for a period of time with a blown head gasket dumping coolant into the oil and overheat atleast once.! The sensor is located under/near the AC compressor. Good luck, hope it all works out either way. Oh wait, sorry, the temp sensor is b y the AC, the oil pressure sensor is behind the intake manifold, next to the distributor. You'll need a special extra deep oil pressure sensor socket for it.