I own a 85 chevy blazer with a 454, the engine is older. Dont know the exact milage or where it came from, recieved it from an uncle who passed away. If i had to guess id say its over 100,000 miles. I would just like any input of what type of motor oil to use. thanks for any help.

May want to start thinking about synthetic if you're not already using, in a 10W viscosity.

On another note, does anyone here use royal purple? I've heard it's pretty nice.

10w40

10w40
Or 10w30 would work.Going to a 5w30 or 5w40 or a synthetic post 100000 mite lead to leaks on seals as it did with my truck when i went from 10w30 to 5w30 non synthetic.Rear main is going out as result of the switch.

I own a 85 chevy blazer with a 454, the engine is older. Dont know the exact milage or where it came from, recieved it from an uncle who passed away. If i had to guess id say its over 100,000 miles. I would just like any input of what type of motor oil to use. thanks for any help.

First of all, what kind of oil does it call for on the oil filler cap.

And dmbrisket 51, saying 10w40 without even asking which oil is factory spec'd to be in there is an unresponsible reply.