2003 VQ (G35) vs 2004 VQ (350z) Engine/Head

What are the differences between the two? Physical if so..

I do understand that the 2003 G35 came with 260/260 hp/tq. and the 350z 287/274 hp/tq.


I see on many sites that the compression ratio's are the same. But is the head different? Are the cams different?

is the upper or lower intake plenum different?

Reason I am asking:


Due to the nature of my car continuing to shoot air into the reservoir tank after countless hours of bleeding I am going to mill the heads a bit and change headgaskets. I happen to have a 2004 350z engine sitting in my garage with a bent rod so I plan on taking the heads out of that engine and sending them off to the machine shop while I await the weekend to work on the G35.

Since I am on a budget I wont be attempting to make any radical changes. Just if the cams are a bit more aggressive on the 350z I may just use them instead of the G35 cams.

Keep in mind I HAVE NO TUNING method. So my next question:


Will I have to radically tune the car in the event the cams are that much so different? ( I know tuning the car will give it the peak performance the car would need ) Just the 2003 G35 came with the crappy ecu that NO ONE except technosquare and im not in the financial status to do such upgrade.

Or will the car run fine just can't take full advantage of the cam switch?

Are the heads any different?


I have searched Google and the forums and have not been able to find cam specs on the 03 G35 // 04 350z if anyone can assist it would be greatly appreciated.

Thanks.

 

Found the 350z specs

http://www.jimwolftechnology.com/wol...INCL_REVUP.pdf

just not the G35

 

2003-2004 G35 and 350Z engines are all the same. No difference.

Different power outputs are due to INTAKE, drivetrain losses, and tuning. You can get a NISMO Z that has different cams though...

 

So basically if I send the 04 350z heads out to the mill and slap them on my VQ on the weekend the gains wont be astonishing









Oh well, it was worth the try...


Ok, so to those who have done this procedure, other than the usual gaskets anything else I should change while I am in the process of this?


my current mileage : 167,000

Car sees an oil change (10-30w Mobil1 synthetic) every 1,500 -2.500 miles.


The engine I have has 58k miles. that being said I am sure the heads are in better shape. I have not done a compression test yet I am very sure the pistons/rings are in good shape.


any advice is welcome, thanks


PS, i will be doing a DIY Head Gasket change for the other users.

 

Are you pulling the engine or are you going to be doing the work right in the engine bay?

You should do a leak down compression test on the cylinders before you do a head gasket swap. A leak down test should show you if you need to do the head gasket replacement.

It could be that you have a water pump that is going bad and allowing air into the system and therefore causing higher than normal coolant temps.

 

How could a BHP rating be affected by drivetrain losses? And how could an almost identical intake (or ANY intake for that matter) make a ~20BHP difference?

It's long been my understanding that the power difference between 03/04 is purely tuning related.