Ok this may seem sorta dumb, but im almost done iwth my k20 swap. And it is a used motor, but i dont know how long its been run. Is there any real break in period with used motors that chances are have been sitting for a while?

 

i wouldnt worry about it.

there is an obvious break in from the swap. like drive around the neighborhood till the car is fully warm, bring it back in and check for leaks. loose stuff, etc. but the engine itself should be more than broken in.

 

yea me and a friend put my ctr motor in and had no reason for break in, like kamin said just check for the little things.

 

just the break in for the new parts. give a new clutch and timing belt a good 500 mile break-in.