So started my cam and head swap the other day and everything is going good other than when I pulled my heads off i got to looking at them and noticed that they are E6se heads and the pistons dont have the normal valve reliefs cut in them. But my question is there any other differnce in the motors than that, i thought that my car being a 1990 HO that it just had the e7 heads on it. And how bad are the E6 heads over the E7. And i am putting a TFS1 cam and GT40 heads. I check piston to valve clearance and it seemed ok as long as i was doing it right. And are the E6 engine still the HO firing order and if not is there any thing i have to change over to make it all work. Any help would be great.