the B16 mannifold is shorter than all the other B series engiens due to the fact that the deck height is shorter. If the Engine is a B16 then a B16 header should fit make sure you have the correct generation mannifold on it. if itsa B16 head on a B18 Block then you will run into clearance issues as the deck height is raised for the Displacment of the B18 Block.

I just reread what was written do you mean Length under the car ? Make sure the exhaust you have is for that car. Ive had issues with some exhausts doing that in my eg Hatch, Coupe and hatch exhaust differ slighhtly in length. Just because it says EG doesnt mean it will fit all EG models. I put a EG Coupe Exhaust on my hatch and it was pushed out cause it was too long. Andmake sure its not a B16 mannifold for a Delsol Which is way shorter than a hatch an coupe.