LSWHO

iTrader: (1)

I want to know:

What RPM have they been successfully revved to?
What type of cam/lobe have you successfully run with them?
How much total lift have they handled?

I don't want to hear what you read. I want to hear what you've done.

RamAir95TA

iTrader: (2)

Do a search for Gizmo and read his build thread. He'll show you how far they are capable of going.

LSWHO

iTrader: (1)

I did. That's what got me thinking. BUT he has a stock lift cam/lobes correct? His RPMs may be higher than normal, but I've never seen that posted. Also, he has a dedicated 1/8th mile race car. Very short bursts if anything.

RamAir95TA

iTrader: (2)

Yeah, purpose-built.

I think anyone running serious RPMs or a serious cam would certainly have no reason to run stock rockers. The more lift on the cam, the more friction on the rocker tip, resulting in lost HP, higher oil temperatures, and increased oil foaming.

IronOutlaw

iTrader: (4)

I've ran them with an unknown stock sounding cam up to 6300 rpms.

Now I'm running them with a hotcam at around 6200 rpms.

GIZMO

iTrader: (8)

The stock rockers that I run on my Stocker have been modified to work with a 7/16" stud. They have also been coated. Valve spring pressure is right around 400 lbs (open). I have never broken one. The kids car uses untouched stock rockers and studs.

I wouldn't run stock rockers if I didn't have to. I would skip over the more common stuff used on here and go straight to shaft mounts.

Contrary to popular belief, I have been down the quarter mile once or twice too!

96lt1m6

iTrader: (31)

I am beginning to think you have

Anyone that runs this class of racing has plenty experience and or has been around those that has....

Thank you Gizmo for the updates,pictures etc. I feel you have shown alot of our members here the Lt1 is and always has been a competitive.

LSWHO

iTrader: (1)

Thanks for the info, what kind of rpm does the kids car see? I keep hearing sa rockers won't handle rpms, but you have stock modified rockers running near 7k.

GIZMO

iTrader: (8)

We shift the kids car at 5400 rpm and it traps a little over 6000 rpm. In the quarter those modified rockers see 7200-7500. I ran box stock rockers for years past 7000 and never had a failure. The reason for the 7/16" studs is reduced flex, which means a few extra HP.

LSWHO

iTrader: (1)

Thanks for all the info Giz. You've had/have some amazing cars.

Wicked94Z

iTrader: (26)

The flex and geometry will hurt you. I wouldn't go past .550 lift if you're looking for some longevity out of your valve guides. I've run em with 918s, about 140/340 and they did fine for the 2000 miles I had them on there. Keep in mind that flex is NOT what you want in your valvetrain.

LSWHO

iTrader: (1)

Yeah, I'm mostly concerned about lift. I have a 563 (w1.5s) lift cam. It won't see past 6k rpms until I can upgrade to NSA equip.

96capricemgr

iTrader: (1)

Given street miles with a meaningful cam it is possible to spear the pushrod through the stock rocker.

Basically what I am saying is "what works" and "for how long" are BOTH factors.

LSWHO

iTrader: (1)

Not that I doubt you but do you have a link?

I am thinking of getting some split ratio (1.5i/1.6e) magnums. Not pro-mags. Until I can dump considerable amount more into the valvetrain...

Wicked94Z

iTrader: (26)

The cam isn't going to "spear" a stock rocker, the pressure the spring is exerting might. LT4 springs run ~330lbs/in and GM uses them with stamped rocker arms in their crate motors.

LSWHO

iTrader: (1)

Probably both from the sound of it. Gizmo said he was running 400# open on his.

JAKEJR

At least one of the manuals I have mention the possibility of a pushrod(s) punching through a stock rocker arm's pushrod cup.

My take on this: stock rockers, stock springs adhere to the factory redline. Aftermarket cam/springs go with aftermarket RRs.

Jake