[pgtr]

Threaded vs Pressed Rocker Studs (SBC)

I wondering 'if' or just 'how' beneficial the threaded studs are for an engine such as mine? Older SBC 350 from early 70s, 2 bolt main, iron heads w/ orig pressed in studs, built for low RPM torque - idle-5500, hydr cam, 9:1CR or so.

And if not just what are some good scenarios or rules of thumb for when it does become advisable? I 'think' Chevrolet started installing these originally on certain HP engines like maybe the L82. If so, was it because of power levels? Cam profile? RPMs?

And what about upgrading to a hydraulic roller cam? Not a 'radical' cam but of similar duration/lift to my current HMV260 (Crane).

thanks,

[strikingthematch]

In most cases screw in studs are used once you reach a certin high spring pressure such is common with large cam profiles. As for any set spots where you will need it I cannot say for sure. However when you start to getting up there in cam profile the need becomes greater as sometimes you can pull the stud right out of the head and there is a good chance you will be doing some repair work then.


Chris

[Dubz]

As mentioned higher spring pressures will press on the studs more pulling them out easier. It would be a large guess as to what pressure they would come out at though.

[roys63]

If you are rebuilding i would have the studs pined on a low budget deal and small lift cams or a stock rebuild. Just cheap insurance, real pain to repair when one pulls or they start pulling.

[Deuce]

I have ran the Z28 solid lifer camshaft (1969 one) and springs in basically stock SBC's with no problems. I believe the 1970 370 HP 350 was the first SBC with screw in studs from the factory. I know 69 Z28 302's do not ( or my new one did not).

If you have the heads off...........most machine shops can convert yours to screw ins for a reasonable price.

Cheap insurance IMHO.


A hydraulic roller camshaft conversion would help the fuel mileage but would not be cost effective for a lot of miles.

I would just find a later model block that already has the hydraulic roller and build it. They also would have the 1 piece seal rear main.

[johnsongrass1]

Scrwein studs are also stronger. They will deflect less than a pressed stud and can hold there valve geometry better. Pulling studs is the first thing to occur with 350 pound spring pressures.

[roys63]

Screw in studs are the best way to go, pined studs will work just fine they have for years, cost now days about $60 at the most . Machine Work involved to install screw in studs and the cost of the studs, $200 +. I have run up to 488 lift cams with out problem's with just the press ins. This is one way to save some Cash on a low budget rebuild. One problem you can have with the screw in studs is some of the push rods won't line up to the rockers with out binding on the head guide and you have to drill out the head and use guide plates and hardened push rods , Even more machine work and more money in parts!

[302 Z28]

The comment on screw in studs flexing less is right on and screw in studs should be a consideration for any hi po engine. Just take a look at the mounting base of a stock Chevy screw in stud, it's at least twice the surface area of a pressed in stud. The fact that they will not pull out with high spring pressures is an added benefit.

Vince