im about to get cams for my NA 05 5AT 350z..so i see that above 11mm i will need new valve springs..will 11mm+ cams give me more power? whats the difference? and does it only end with changing the valve springs?

 

If you go that far into the engine why not just do springs?

 

u mean 272's with springs r worth it?

 

In my opinion cams on a NA VQ motor are a waste.

However, to each his own and if you are going to put cams in a NA motor you might as well rev as high as possible.

 

if you do springs then you should just do 1mm bigger valves because you need to take your heads off to do valve springs, new head studs, just send it to a shop to do PnP too... it could be a never ending thing. if you do any thing to your heads just build them no point in just doing cams..

 

and there is no point in doing +1mm valves on an NA Z either unless displacement is increased significantly...and even then, I still wouldn't bother investing the $. Head work is one thing, but stock valves are plenty. Oversize ones will mean more machine work, more cost, more weight, but no real gains overall. You can only suck in as much as the engine will pump in the first place. Stock size valves are not a choking point. There can be some cfm gains via use of an aftermarket, stock size valve, as the underside of some have a nicer overall shape vs stock. Depends how crazy you're ultimate goals are. Doesn't sound like the OP is in that realm

That being said, cams on a non revup, automatic Z are similarly a waste. Stick to the bolt ons and tune, and save doing the cams for when/if you decide to do a full motor build. Over 11mm and you'll need more than just springs. You'll need pistons....