I believe the Valvoline site states that Maxlife can be used in new and rebuilt engines. Would be wise to consult the oil company for the particular brand you plan to use (most have 800 tech numbers, or do email for a written response). You may also want to consider warranty requirements as some of these HM oils may not fit. I believe the Quaker State does not even have the API doughnut on the bottle. A look on their website indicated it is only SJ. Valvoline Maxlife, on the other hand, does have the doughnut and it states it is an SL oil, which should meet the warranty requirements, provided you use the manufacturer's recommended viscosity grades.