LOOK...going to look at a car tomorrow
GM's actual specs are hot idle of 6psi, 12psi at 2k, 24psi at 4k. I'd feel more than a little concerned if mine idled at 6psi personally though, most LT1s are significantly better than that obviously.
When the car is completely cold, it should hold around 45-60.
If I let my car idle for about 20 seconds, then gas it up to about 3500 rpms, the Oil pressure will jump a couple pounds and stay there because you just exercised it the lines and pump.
But w/o doing this, it should hold more than or around 40-45 easily. ( cold @ startup)
When its completely hot at an idle in Park, you want the oil pressure around 20. Anything lower than 18 is not a good sign.
Other thank the occasional opti-problem, LT1's are very reliable and 180K on original motor parts is easily attainable with proper oil/fluid changes and care.
I bought my Z with close to 80K, and its still very much strong.
It gets cold up here in Upstate NY, and I leave my car on the road until snow falls, or its in the forecast.
On some very cold mornings, ive seen 70 pnds of oil pressure, although this is common for a motor in 10-35 degree weather.
Look underneath the body, wheel wells, and floorboards to make sure its still solid.
Its also helpful to see who owned the car before you, and how he takes care of his/her vehicles.
A beat Fbody is easy to spot.
Possible Signs Are:
-Dirty and dusty under the hood.
-Cracks in the dash or console
-Multiple rips or tears in upholstery
-Missing radio/function buttons. ( the interior of Fbodies are nice, but arent the best in terms of quality, and it usually easy to spot abuse.)
People who abuse the inside, probably abused the car in general, and that means the driveline might have taken some punishment.
Good Luck Jco,

