It really depends. Depends on the rocker type, depends on your shift points, depends if your old springs are worn out enough to see valve float. Stiffer springs are generally only necessary if you are experiencing valve float or are expecting it. They also stress your timing chain more. I honestly wouldn't change the valve springs unless I knew I had to. Like I said, they won't add horsepower unless your old springs are causing an issue.

 

Sounds Good. Well Im going With ZZP Modified 1.9 Rockers, (Not roller rockers) My car only has 92 000Kms ZZP says I should be fine with stock springs.

Also Is Fine to Run 1.9rockers with stock pcm for few months? Once I save More cash I was thinking of finishing with zzp Pcm, 3.5pully, Plog

How would You know if valve springs are floating??
Thank you,

 

You'll be fine running it without a tune, but I'd get a tune as soon as you can. Do as many mods as you're planning on doing before you get it tuned. Having the pcm tuned for your mods really makes a big difference.

Also, a custom tune is generally much better than a pre-tuned pcm assuming you can find someone that knows what they're doing to do the tune for you.

When the valves are floating, it usually causes loss of power and misfires at high rpms. (valve float is the valve not closing the whole way when it's supposed to, or bouncing off of the head).

-Riggs.

 

Thank You Biggriggs

But I dont Think I would Be able too Find anyone Here to Do a Custom Tune, Not many Performance places's here,

I know Once you Start Modding You can't Stop, But As For proformance I just wanted 3.4Setup . After Research Evry were I ask I always hear With 1.9Rockers,Plog,cai,pcm,180Stat on a 3800sc Monte I should not go to a 3.4 And should Go once size up 3.5. So thats Probably What Im going For. Would Love More POWER on my 05 MONTE but thats what my 73 Chevy Nova Is for.

Thank you For You Help Any More Info Would Be GREAT.

 

I wish I still had my 74 Nova...

 

An L67 with a plog/rockers/tune is usually ok running a 3.4, but make sure you have a way to scan for knock...it's not guaranteed that you won't see some kr with that setup.

I wouldn't recommend going to a performance shop for tuning. They generally don't know how to tune v6 cars. Your best bet would be to find someone local with a PowrTuner or HPTuners and have them do a street tune. Usually cost a good bit less than a vendor PCM, and the tune would be tailored specifically for your car (just make sure the person doing the tuning is credible and has experience tuning).

 

74 Nova Nice!! Almost Exaclly Like Mine. My 73Nova Was My dads it was his 2nd car and and he gifted it to Me 2 years ago. Frame Has Been sand blased and Boxed and Painted same with engine compartment.. Body is sanded Right to Steal. and Both rear Quater Fenders are Half way Done. And Interior IM NOT SURE ON WHAT TO DO YET. its Not orginal Might ROLL cage and drag it. Or make it street/race. I have a 396Block but Needs Rebuild. Im looking at A 350 with tranny thats running to drop Into it for now. and rebuild 396..

Awsome Thank For all the Help I know what Im Going With now. Deff going to get a knock scanner.. With plog/rockers/tune is usually ok running a 3.4. What Would Make 3.4 pully knock FREE? headers Insted Plog?

 

Yes...