When is too late to switch oils?

[triggz]

My 2000 GT has ran on motorcraft 5w20-5w30 all its life at 3-4k interval changes. I'd really like to switch over to something more race-friendly...

Is 43k too late to switch to synthetic?
If not, when is?

 

[bdcardinal]

its not too late to switch. generally i would think that its too late to switch if you have a big oil leak or if you are burning more than 1 or 1.5 quarts of oil inbetween a change. i changed my crown vic at 50k (mobil 1 5w30) and if anything it ran better.

 

[YardSpecial]

Never, ever TOO late.

I have proved that in my own tests.

 

[WRXracer]

yeah

you can go back and forth as much as you like.. its just oil hehe..

 

[03-s281]

I just switched to Royal Purple.
I know a guy that had his LT1's oils switched to Royal Purple
Gear oil and motor oil and picked up 10rwhp on the dyno.
He had it done on Hot Rod TV.