I have a 12' mustang gt stick. I only have 300 miles, however, I took it to 6k rpm in 2nd gear 4 or 5 times already. People say the new engine is still breaking in and taking it up that high in the rpm range is bad for the engine is this true? I hope I didn't damage my engine i'm worried to be honest. I never red lined it and the highest I took it to was 6k rpm maybe 5 times.

 

You're fine.

 

you should be good, but i'd take it easy til you at least hit 500mi

 

I had always read where you need to break the clutch in for 500 miles so high revs would be a no no until then.

 

No.

High revs don't affect the clutch any different than low revs do. What you are not supposed to do for the first few hundred miles are:

1) Dump the clutch at high RPMs

2) Powershift

I am a firm believer in the "break it in like you stole it" method, which I performed on my '12 MT. It runs like a champ.

These engines are 90% broken in within the first 30 seconds of operation, which happened before you ever saw the car at the factory.

 

Now that you're at 300 miles, I recommend at least a run to redline every 100 miles or so. Let the engine revs fall naturally back to 2-3K (i.e., don't redline then brake immediately). I've had success using this method which supposedly helps seal the piston rings and avoid future oil burning situations.

 

I'm with Hawkeye. I am of the old school that says drive it out of the showroom the way you are always gonna drive it.

I have been doing this to new cars for 39 years and haven't lost a motor (or clutch) yet!

 

You are supposed to vary the RPMs when breaking it in. I don't know how good revving up really high is for it though.

 

It's a mustang, drive it like you stole it.....jjk. No seriously 6K is not bad I do it hard through 4th gear about once a week.

 

Agreed Hawkeye! Break it in like a beast and it'll be a beast. You gotta train em young! Whenever I've built a motor, I followed the 20 minute run for the cam, after that, wide open till ya see God, then brake!!