I dont see the use for 600 mile break in. Like Richmond gear website said a couple heat cycles and your done. The reason an engine needs breakin is for the valve seals andfor the valves to create a good seat.

 

Most of the women you will meet,are already broken in.!!!

 

Now that we know is a fact.

 

I've installed a lot of ring and pinion sets in Camaros for street and drag racing. You do need to follow the instructions listed from Richmond above. The new bearings and gears produce a TON of heat when brand new because you are talking incredibly tight clearances.

Also, believe me, change that rearend fluid to get all that metal out of it. Me, I'll change mine around 5,000 miles, again at 15,000, then regular interval. Cheap, and easy to do.

Someone asked about "backlash"....You have to decide if you are using the car for street driving or drag racing. For drag racing, you do not want the teeth to "bang" into each other when you launch, so you set the gears up differently than for street driving. They whine like crazy when you set them up for drag racing, but will live longer when launching.