At what kind of rpm/hp levels does it become wise to upgrade? I've heard so many different answers concerning this topic I'd like to hear some more opinions.

 

I'd say above 6500RPM or so. Along with a stud girdle, that'll pretty much cover you. Until you want to be above 7500RPM or so, when a shaft rocker system starts to look good.

 

That is what I was thinking too. I guess I should get some 7/16" because I'm trying to build a 475hp 350 that spins about 6600 or so.

 

What cam? That's usually what i'd use to say either way, if you should upgrade or not.

I like the thought of using a stud girdle instead personally. I think it does more by tying into the other studs to use as support. You just need tall valve covers.
With the 7/16" studs you need the bigger rockers, which are sometimes (usually) more cash.
Also, if this is a solid cam, i'd recommend the stud girdle even more.

 

Hydraulic Roller, 231/237 .596/.591 113 LSA

With 203cc heads I figure it should peak 6000-6200, so worst case scenario shifting at 6600. I put the Proform "tall style" valvecovers on last year so I'm hoping they will clear most rocker arms/stud girdles.

 

That's a sexy looking cam, who makes it?

Look at BTE's stud girdle, $59 is a damn good deal for a non-crappy j hook style one.
Then look at extra tall poly locks.

 

No debate. If you have the choice go with the 7/16" studs. You want to keep the flex at a minimum in the valve train.

The idea is to transfer the profile of the cam lobe to the valve. The more things are springing along the way the less that profile gets transferred.

You will also want a stiff pushrod for the same reasons. You don't want one that will pole vault on you.

 

If you've got to buy new rockers anyway then you might as well do the larger 7/16" studs. They don't cost much more than the smaller 3/8" rockers and provide a stronger, less flexible fulcrum point for the rocker.

Any time you can add strength and stability to the valvetrain basically for free, I'd do it.