GM tends to recommend 5W-30 oil.
by the oil filter, under engine.
this is normal, when the car is cold or off. the oil sinks down in to the oil pan.,. If this is a GM engine you may be using an aftermarket oil filter that allows oil to drain back this is not a good thing and can cause engine damage. GM has a TSB on this very problem.
I highly recommend that you buy your crate engine from GM. Quality and cheap, are incompatible. You get what you pay for. With a GM crate engine, you will not be disappointed.
10W30 any major brand.
what size engine
5QTS. with new filter.
The normal oil pressure on a GM 305 engine is between 40 and 60 PSI depending on the model year. High oil pressure is needed to allow for proper circulation through the engine.
The oil pressure may vary depend on mileage. However, typically on a 1988 GM engine should be around 14.25 ohms or more.
It will tell you on the oil fill cap. A GM 4.3? You did not specify.
10w40
80lbs