Installing K&N on '72 SUs

[KingTutVII]

Hello everyone.. I have just ordered the K&N filters for my 1972 240z. My question is: What will I run into when installing these in place of my stock air box (any lines that need to be moved or additional filter I need to buy)? Any help would be appreciated.

[Gary in NJ]

The stock airbox works quite well. The SU's need the airhorns that are part of the stock box to provide good flow at low rpms. You can purchase separate airhorns. Z-Therapy might have them.

You will need to install nipples on the backside of the K&N mounting plate to accommodate the vent lines that were connected to the backside of the stock box. Additionally, you will need a separate breather filter on the valve cover.

Edited April 5, 2011 by Gary in NJ

[pbarcher]

I have been using the K&N's on my Z for decades, but only recently added air horns from MSA because of posts I read here. What a difference! Picked up signifcant power at higher RPM.

[5thhorsemann]

mesage deleted because I'm an idiot!

Edited April 5, 2011 by 5thhorsemann

[Bruce Palmer]

Agree with Gary about the stock air box. Nice air horns built in, both carbs get to breath from the same air source (good for balance) AND can be plumbed through the core support to a filter in front of the radiator where cooler air lives than that boiling up off the exhaust manifold.... Nissan could have solved a lot of problems with a cross flow head got the L series engines.