I recently overhauled my 1975 360 engine. I completly went with all new parts including valves and oil pump. I replaced the Intake Manifold with an Edelbrock 390 preformer and installed a edelbrok 1406 electric choke carb. I have about 2000 miles since the overhaul. my problem is the engine uses a quart of oil every tank of gas, (about 250 miles). It has 60 psi oil pressure upon start up, but drops to 25 psi at hiway rpm and down to 10 psi at idle after the engine reaches operating temperature. The engine runs fine (no lifter noise or knocking). It does not smoke. What would you recommend I should do to determine the problem?
first thing you have to do is find out where the oil is going. at a qt./250mi, I think if it were burning it it would smoke noticeably. I'd drain some coolant out and see if it's in there. I'd also check the air cleaner housing, and check all vaccum lies. you might also want to crawl under the truck with it running, it's possible that its leaking only when it's running, pay special attention to the area around the oil filter adapter.