Mileage is really no indicator. It goes more by like how well the engine was cared for. Somewhat regular oil changes and tune ups, you could see 250,000 miles. Non-turbo engines might last a bit longer than a turbo engine, especially a modified one. I have 165,000 on my 85. You'll find seal replacement and other things are probably required long before a new engine is.JB072 said:What is the average milage that the 1987 300zx 2+2 car will go before the engine goes.