Originally Posted by SurfDog

My PITA VQ37 Humptey Dumptey motor rebuild is finally coming together (again) this week! I'm hoping to be breaking her in next week. (again)

The JWT recommended break in and tune cycle looks like:
1. run motor in neutral 2000 rpm for 15-20 minutes to break in head. DO NOT IDLE!
2. run motor easy (1/2 to 3/4 throttle in 2nd gear) low rpm up to 5000 and engine break back down 10 cycles to seat rings on new block
3. 300 miles easy driving using normal new motor break in procedure to seat rings and polish bearing surfaces. Go easy due to poor tune from swap from C1 to C2 JWT cams...
4 change oil
5. Retune/Dyno!

6. (my addition) See if it still sounds like a box of nickles. If not, drive around with a pit in my stomach for 6 months wondering if its going to blow up/ self destruct again.

wish us luck!