best oil for high mile firebird?

[jd1666]

whats the best oil to use in your firebird with high miles on it? (over 100,000)

[nhraformula]

just change it every 3-5k miles. brand doesnt matter.

[jd1666]

i change it ever 2500 but ive never used synthetic oil and heard its pretty good

[yellowv]

I use Castrol GTX 10w30 at 3000 mile intervals. With 133,000 miles I burn less than a 1/4 quart between changes. No reason to do 2500 intervals.

[gd1996]

I don't synthetics, look how thin it is when you take it out after 3k. I like a thicker oil especially in summer 20-50 is what I run.