Got a '91 300zx non-turbo, 5speed..When accelerating quickly the rpm's increase as if the clutch is half way in. Feels like all the power isnt getting to the wheels...Im new to the 300's but it cant be normal.

 

Your clutch is probably bad.

Put it in 5th and floor it. This puts the most strain on the clutch, as the engine wants to race but the gearing won't allow it. If the rpms rev freely without the car accelerating as it should, the clutch is blown.

 

Thanks I appreciate the info!

Now how do I properly break in a new clutch?
..the previous owner obviously didn't know how

 

Take it easy for about 500 miles. DO NOT powershift. You can accelerate as you wish once the clutch is fully engaged, but shift gently.