Ashyukun Reader
March 7, 2013 9:30 a.m.

While chatting another gearhead who was over picking up some parts from me, we were looking over and discussing the Vortec heads for my Challenge car's SBC, and he mentioned that if I was using a higher-lift cam (which I am) with heavier springs (which I also am) that I pretty much needed to ditch the stock pressed-in studs on the Vortec heads in favor of screw-in studs because the added force would rip the stock ones right out and obviously do unpleasant things to the parts involved.

The engine will be using a Z04 roller cam initially, and later (once I'm not constrained by Challenge budgeting...) a GMPP Hot Cam both of which have a max lift (with the 1.6 rocker arms I'm using) of about .525. The valve springs are a set of performance springs that while I don't know the exact details on (should be getting them tested in the next day or so by the head shop I've had doing work for me) on, they're solidly stiffer than the stock springs. The Vortec heads have had the necessary machining done to handle the higher-lift springs. I initially had hoped/planned to use Nitrous for the drags, but it's increasingly looking like that's just not going to be in the budget cards.

What's the concensus here about whether the screw-in studs are really necessary? And if they are going to be required, is that really something that I need to have the machine shop do for me, or is it something that I should be able to handle myself? Some searching around seems to indicate that with the proper aligning tool and tap that it's not that hard to do yourself, but the guys at the performance shop here locally spoke of nothing but doom and disaster from people they knew who'd tried doing it themselves...

Rad_Capz Reader
March 7, 2013 10:33 a.m.

Pinning the press in studs might be an option for your application. This could possible be more easily done at home. To see the steps involved in installing screw in studs look here although I wouldn't try it at home. http://grassrootsmotorsports.com/forum/grm/81-malibu-performance-therapy-project/23056/page1/

dinger Reader
March 7, 2013 10:55 a.m.

At .525 lift, yes, you're going to want to do do something about those press in studs. You can either pin them, or replace them with screw in as you mentioned. The shoulder style studs mentioned above need to be done at a machine shop for them to be done right. You can also use a stud without the shoulder, which just requires the hole to be tapped.

http://mr-gasket.com/scrw-in-r-arm-studs-3-8-16pc.html

Like you mentioned, you will need a tool to make sure you tap the hole square, but it is something you can do yourself.

HiTempguy UltraDork
March 7, 2013 11:02 a.m.
Ashyukun wrote: I initially had hoped/planned to use Nitrous for the drags, but it's increasingly looking like that's just not going to be in the budget cards.

Nitrous will be worth more than a cam at the drags. You won't need more power for the auto-x (might even make it easier). Win-win.

Ashyukun Reader
March 7, 2013 12:39 p.m.

I'm planning on going by the shop after work today to discuss it with the machinist- I had been looking at the shoulderless studs where all I'd need to do would be to pull out the pressed-in studs and tap the holes, but I'm not wholly certain that I can use those and don't need ones with shoulders to raise the rocker arm up a bit. It will also depend on how much he'd charge to do the work.

HiTempguy wrote: Nitrous will be worth more than a cam at the drags. You won't need more power for the auto-x (might even make it easier). Win-win.

True- but the cam the engine came with was not anywhere near performance (stock TBI truck cam) and would have been quite a dog for both auto-x and on the strip. It's not totally set that I can't use the nitrous either- it will depend on how other things I had to do go and how much they cost.

914Driver MegaDork
March 7, 2013 1:22 p.m.

Plan B: They sell a kit that puts a roll pin in perpendicular to the stud. It's easier and cheaper.

Stud is 3/8" diameter, a screw in stud is 7/16" so all you have to do is tap it (straight)

It's not difficult, just a PITA. I would go for the pin kit myself.

Dan

http://www.chevyhiperformance.com/techarticles/148_0208_vortec_heads_valve_lift/viewall.html

Read this.

Ashyukun Reader
March 7, 2013 1:42 p.m.
914Driver wrote: Plan B: They sell a kit that puts a roll pin in perpendicular to the stud. It's easier and cheaper. Stud is 3/8" diameter, a screw in stud is 7/16" so all you have to do is tap it (straight) It's not difficult, just a PITA. I would go for the pin kit myself.

I'll have to look into that, since the GMPP rocker arms that I got for a nice challenge-friendly price are made for stock (3/8") studs.

http://www.chevyhiperformance.com/techarticles/148_0208_vortec_heads_valve_lift/viewall.html Read this.

Already have, or at least a very similar article. All the spring seat/valve machining has been done- I just didn't realize I'd need the studs upgraded too...

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