Chevrolet: Low Oil Pressure, low oil pressure, chevy c

Question
Let me start by saying, before you do, "That was really stupid - stupid.

With that out of the way let me explain my situation.

I have a 1967 Chevy C-10 with a 350 engine.  All was well until (here it is) I put about five gallons of diesel in.  I didn't notice this until about five miles down the road.  The smell and the blue/white smoke informed me of what I had just done.  I immediately pulled into another gas station and put about $10 of 87 octane in.  I have driven about 20 miles so far and I have starting noticing a big drop in oil pressure (oil gauge at about 20 - normally around 40, engine knock, and reduced power).

Today I drove the truck for the first time in about a week.  The gas leve was very low and I put in just over five gallons of 93 octane.

Needless-to-say, I know where I went wrong, but what do I do now?

Thanks for you help.

Answer
Gene;
 HI  well the first thing is get a can of gas and some matches , lol, no for real I would siphon all of the gas out that you can get out of the tank, than if you can open the fuel line that goes to the carb and turn the engine over a few times to get all the rest of the gas out. than re hook the line up, replace the gas filter if you have one and if not put a in line filter in it. than fill the tank about 1/3 the way with good gas and a can of dry gas and a can of stp gas treatment too. and than drain the oil and replace the oil filter, put in some good oil I would use a st. 30 wgt. oil and add a can of stp  oil treatment.and than remove the spark plugs and put new plugs in it. than get a can of carb. spray cleaner and spray the hell out of the carb ,inside and in the jet area , etc, clean it good. now take it for a nice long ride at about 45 miles a hour and let it clean itself out a bit, than when the gas is low fill it with good gas and a can of stp gas treatment and check the oil,if the oil looks thined out change it once more and a filter also. and a can of stp oil treatment. than after all that you should be fine but do not race it to much till all of the old fuel gets out, ps check the gas filter to.  you should be ok after you do all of that to it., do not feel bad you are not the first one to do that and you will not be the last one.  ok ...>><also check the plugs after 100 miles as they might have to be cleaned.ok