Vortec heads 3/8" press in studs and rocker options

[Justa1time]

Good evening,

I have a a set of stock casting vortec heads. I am looking at self aligning rocker and rocker stud options. Currently I have the factory 3/8" press in studs.

- vortec as cast- no porting or modifications.
- Alex Parts Vsk4h53
- 130 Lbs @ 1.775
- 318 Lbs @ .500" Lift

Aparently good to .550 lift. Will verify now they are installed.

Cam:
.340/.340 lobe lift

- Ferrea Stainless factory sized valves.

I had planned on using the stock 1.5 ratio stamped steel that I have a very low mile.

Should I consider different rockers?

Hartland sharp said they would make a 1.5 or 1.6 ratio on a 7/16 self aligning rocker.

Scorpion only offers self aligning rockers on a 3/8 stud

My main considerations for running an aftermarket rocker is due to the body being machined instead of stamped and I would think that would be more consistent. I have looked at the GM 602 crate and see it uses a 1.5 stamped rocker. Not sure on the 604.

Do I run it how it is with stock rocker ratio and studs? Do I buy scorpion 1.5 and rock stock studs? Do I run scorpion 1.6 and stock studs? Do I move to 7/16 studs and run Harland sharp? Do I buy some aftermarket stamped rockers in 1.5 or 1.6 and run those?

Thank you,

Bryan from Oregon

[C.A.R.E.]

I all ways replace the self align rockers on any performance heads with screw in studs and guide plates with non self align rockers. If you float the valves or break a spring the self align rocker can move over to the side and open the valve more and possibly make the valve hit the piston ! Then you have a mess !

[dannobee]

Not only that, but the studs themselves can pull out when used in high performance applications. Better to put the screw in studs and guide plates now, rather than trying to fix a pulled stud or three in the car.

[F-BIRD'88]

The oem stock vortec head rocker must be checked for rocker slot to rocker stud clearance at max lift.
If it clears (.030"). I think you are good to go.
Otherwise get longer slot self align rockers or grind the radius of the slot in the rocker a bit longer.
Longer, not wider.
The studs in the vortec heads don't tend to pull out like the studs in the old heads.

[F-BIRD'88]

If the cam is solid lifter type use round wire feeler guages VS flat feeler guages to set valve lash with self align stock rockers. Use only tight lash cams. (.016"±)

[F-BIRD'88]

New stock type rockers can tend to run hot from ball on seat friction untill the break in.. Nice to run with low low stock spec mild spring pressure and lots of oil lube at first to allow easy break in, simular to flat tappet cam lifter breakin.. Once run in that initial heat and friction decreases. bit of Moly in the oil helps. A lot if racing motir oils have Moly as an anti scuff anti wear additive.
But you can add your own... GM EOS is good too.
Lots of oil flow lube and cooling is key.

Then reinstall yiur high perf valve springs to spec.

I use old stock sbc valve springs set to max tall installed height (1.75"+++) for mild spring force to run in new stuff. If on vortec heads pull the spring dampers out.

[BOOT]

I've herd that vortec studs don't pull as easy as older heads But I've had studs pull on an engine. Then I pinned them and then they bent and broke.

It's not the cam so much as it's the springs that the cam needs that pulls studs. Higher ratio rockers will only make it worse as they increase intensity.


My vortec stud video https://youtu.be/eZlhl9kzZXM

[dfarr67]

Take it from me- although my vortec builds have been mild with no issues with the 3/8" hardware. I've gone the long way around to 7/16"- save money and go direct to ARP 7/16" screw in studs and good steel conventional roller rockers.

[1980RS]

I ran stock self aligning rocker on my 406 Vortec headed 10 sec ride. No studs pulled or any other trouble. I only used the stock rockers (longer slots) to keep the weight off the tip of the valve for an increase in RPM potential.

[F-BIRD'88]

Many don't realize that the stock rockers are light weight and low mass where is matters. (outboard of the pivot point center) Less moving mass = less spring force required= less deflection.
While when brand new friction is higher, it decreases quite a bit and settles in once the rocker seat and ball get friendly.

The heavier the rocker is (the outboard parts) the more spring force needed for x valve motion and y rpm.

[BOOT]

Many don't realize that the stock rockers are light weight and low mass where is matters. (outboard of the pivot point center) Less moving mass = less spring force required= less deflection.
While when brand new friction is higher, it decreases quite a bit and settles in once the rocker seat and ball get friendly.

The heavier the rocker is (the outboard parts) the more spring force needed for x valve motion and y rpm.

Been saying for years wish they made LS style roller but with foot tips for SBC. Still think someone said that the roller tip helps the often crappy geometry of the SBC. And I'm also not a fan of stamped rockers.

I know there was a test that showed the aftermarket roller tip LS rockers wouldn't rpm as much and it seems many use the stock upgraded trunion footed rockers.

Also once read an engineer say 'Roller Tips Sell Rockers!"

[dannobee]

I guess we should ask is how will you be using the engine? Because in circle track racing, it's commonly known that stamped steel rocker arms fail, in all kinds of different ways, with the most common seeming to be a "rocker on a stick," where the pushrod breaks the ball part of the rocker out and sticks through the hole. I've also seen them split along the body of the rocker and also break the rocker balls into pieces. But if you're not limited by rules, the Harland Sharp's might be a better alternative.

[F-BIRD'88]

If you are splitting rockers or smashing rocker balls this indicates severe shock (hammer blow like) in the valvetrain. Valve float, bounce, crash. Rocker slot striking the stud at max lift under valve float. You are doing something wrong.

[dannobee]

Yeah, yeah, sure. As if EVERYBODY who is forced to run stamped rockers is doing something wrong...

In some classes there are things called "rules," where you are FORCED to run certain valve lift, valve springs, and rocker arms.

Maybe you should go circle track racing for a few years and teach the rest of us how it's done.

[F-BIRD'88]

Not everybody races dirt oval. Sorry bout your luck re: rules. Rocker arms that are being hammered , fail.
Same with pistons.