1988 started the use of the 4.5, so the engine will be fine.ide stay away from the 4.1s
They still have it (ZDDP), just not as much.Do exactly what NOTAGURU said. Low mileage old cars are a potential headache if not serviced completely. I would also check the rear drum brake wheel cylinders for fluid seepage now and a month after driving. Make sure you use the GM sealant pellets as per decal under hood once the coolant is replaced. I also use DELLO engine oil labeled for use in a diesel. These engine required the zinc additive in the oil for cam protection. Diesel oil usually has this additive where as new oils dont.