OK, so this is what I did, and this is what I have. 65 Mercury with a 390 2 bbl. Carb needed rebuilt, water pump went bad, soooo picked up a reman Holley 4bbl, (600 cfm), a used Performer intake, and a new waterpump. Put everything back together, car starts in about 30 secs. of cranking. So far so good. Warm the car up to set the timing, notice the oil pressure climbs from about 50 @ 700 idle, to pegging the gauge! Turn it off, start the engine, oil pressure is back to normal for a minute or 2 then pegs again. Using Mobil Delvac 10-40 and a K&N filter, 6 qts. Before the changes oil pressure was about 40 or so at a 500 idle. The engine has about 87k, doesn't leak oil from anywhere so far, but the idle lopes a little, suspect a vacuum leak, another new symptom. Anyway, I'm looking for some guidance and I appreciate the help.