Gripenfelter

At what point should you switch to a 7/16" stud over a 3/8" stud for rocker arms?

30thannZ28

I use the 7/16" ones for peace of mind.
see sig

shoebox

Big lift, high rpms, race or play around a lot..those are good clues it would be a good idea. They are so cheap and reasonably easy to do (more so if you are getting new rockers at the same time) that it is just good insurance.

SVT Killer LV

There really isn't a correct answer for this. I suggest the swap the first time you do rockers on your car. I changed mine during the h/c/i swap on my car. Whenever you chain the valvetrain geometery added strength and sturdiness is a good thing. IMHO... this next motor I am building will have 7/16 rockers AND a rocker stud girdle...

It's just cheap insurance

350 HRSS

I agree. I went to 7/16 w/ my LT4 Stage II heads. IMO, it is worth it. I posted the same questions here at that time as well, and received the same kind of answers *hint hint*

ibanez6rg

I'll be using 7/16.

OldSStroker

I'd switch at the time I needed to go to 3/8 dia pushrods (on a SBC) for adequate stiffness. IMO, first make sure you are using the stiffest rockers available. Good 3/8 studs like ARP probably deflect considerably less than some rocker arms.

Thought: on a SBC, or any head with inline, non-canted valves, the bending loads on the studs tend to bend the girdles in their weakest direction, and they may transfer any bending in one stud to other studs. BBC girdles make more sense to me.

My $.02

FacelessZ

I just went with my stock 3/8 stud after I installed my GMPP 1.6 rockers. After I get springs and pushrods I'll be switching to a 7/16 stud just for peace of mind with the lift of the XE 230/236...

Gripenfelter

Thanx guys.

I guess we'll be going 7/16".

OldSStroker

That means new rockers as well as head machining, right?

No flame intended, but what "peace of mind" do stiffer rocker studs give? Studs are not the weak link in the valvetrain. We're not talking about them breaking, just deflecting a few thousands of an inch. IMO, spending the bucks on stiffer rocker arms (which deflect a lot more than studs) will probably put you farther ahead toward a stiffer valvetrain which allows the valve to more closely follow what the cam is trying to do.

My highly-opinionated $.02

FacelessZ

Thans for your input, but seat machining won't be necessary with the Crane 99893 springs I'll be getting...

I got such a great deal on these rockers, that's why I went with SA...if I feel like it (not an avid track-goer) I'll sell them off and go with a set of NSA 1.6 rockers with guide plates...and 7/16 studs...for MORE peace of mind...

OldSStroker

FacelessZ

In that case I'll stick with my 3/8 stud until I order an alternate set of heads to be sent to the shop...

shoebox

The thread size in the LT1 head is already 7/16", so there is no head work to be done for the studs that are 7/16" on the top end. Both 3/8" and 7/16" studs are 7/16" on the head side.

OldSStroker

Cool! Thanks.