hi everyone...
i have an 84 monte ss. 305ci. i want to use quaker state Q horsepower in her, replacing the mobile1 full synth. i was looking on the quaker state web site and according to them they dont make 10w30 oil in Q horsepower, they only make 10w40. i was wondering if putting 10w40 in my car would be a bad idea.

thanks.

 

not sure the age, miles, and history of the engine but FYI 10w40 is a heavyer oil then the 10w30...

im sure your prob already sold on the Q oil, but i perfer catrol syntec. my car seems to burn off moble 1 when i use it and the castrol doesnt... both are a 5w30 that i use... i have high milage on my engine and i have been thinking about going ot a 5w40 but knowing it is a thicker oil was considering the pumping presureloss by runing it...

 

i use both mobil 1 and castroil 0w30 my motor loves the 0w30 and 5w30 as well but the heaver oil can be a very bad thing. because 5w30 0w30 and 10w30move quick threw the motor and the heads. me personaly chevy and chevys comp ford runs best with 0w30 and 5w30 even with 180,000 on the motor i just redone some valve guide seals on a chevy 3900 and used 0w30 after i was done and it was a completly smouther idle useing a 0w30 because of the higher miles on the persons car and he was very happy when i did the oil he said it got its performance back and asked what i did differently all i said the lighter waight helped out like 0w30 and 0w20 if your motor has or pushing 180,000 go with 0w30. what i am saying if it runs great dont go to a higher weight of oil in the motor. i have done it in the past and ruined the motor you have to think the oil pump has a lot of weir and going to a heaver wieght can be a bad thing 0w30 and 5w30 is perfect for the motor becase if it had 0w30 or 5w30 threw its life dont go with heaver wieght. youll be asking for a engine rebuild