Did head swap to AFR's today, when I pulled off the old ls1 heads noticed alot of black grime inside runners and some inside intake. You can see the diffrence where the injectors hit runners then you see the grim. Is this normal? what do I need to do? How do I clean intake system. Do I need a catch can or something to prevent this?

 

its a combination of normal carbon build up plus the oil the pcv system dumps through the intake. quite normal for ls1's

 

Guess I need a catch can right, well I just bought one??