please help!
 

Yeah so i left for vacation last week and half way up my brother called me and said that he drove my 90 coupe and all of a sudden it started ticking real loud. He drove it home (about 2 miles) and realized that it had absolutely no oil pressure. He then immediately shut it down. It sat all week until i got home this sunday. First thing i did was pull the distributor and sure enough i have a broken oil pump drive shaft. It was pretty well twisted before it snapped. I welded the good long end to a shaft to drive the pump to test it and it hardly turns under a hightorque drill and then it snapped. So i am at the conclusion that it needs a new pump but i will perform a cylinder pressure/leak down test before i waste my time installing a pump with the engine in the car(if thats even possible). Are there any other in-car test i can perform to see if i need to rebuild my motor? Any help would greatly be appreciated. Also the engine is bone stock with 83k miles,the usual rear main leak but ran extremely strong.

A wet and dry compression test, followed by a leakdown test, if necessary, is about the best diagnostics you can do without being able to start it.

Take care,
-Chris