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062 Vortec head question

12K views 28 replies 7 participants last post by  jokerZ71 
#1 · (Edited)
I recently acquired a set of Vortec heads 062 castings. They were a bare set but did have screw in rocker studs. Do these heads come from the factory with screw in studs? Also, do these heads take the standard chevy valve or is it a different style? Looking to build them for a mild street motor, I was told they outflow the old camel hump heads and are all around better stock head for the street. I forgot to ask if standard roller rockers will work on these or do I need a different style. An old dog trying to learn new tricks here.
 
#2 ·
Stock L31's used pressed-in studs, no guide plates and rail rocker arms to center the rocker over the valve stem tip.

Conventional rocker on the left, rail rocker on the right....
http://c564296.r96.cf2.rackcdn.com/Articles/2012/02/08/h07-0312ae.jpg

Here's a rail roller rocker, for use without guide plates....
http://image.mustangandfords.com/f/..._+probe_rocker_arms+rail_type_roller_tips.jpg
Pay attention to the sides of the rocker contacting the retainer. If they do, the game is over because this will unload the keepers.

If the heads have guide plates, you can use most any rocker you want to. Make sure you have clearance where the pushrod comes up through the head.

Here's a tutorial that some of us fellows put together....
http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head

.
 
#3 ·
NOT stock with screw in studs; although some GM dealers used to (still do?) modify them to handle lift over .460".

There are 'drop in' spring and retainer sets to accommodate more lift. StraubTechnologies is one source, along with Alexs Parts and others.
 
#6 ·
We have a Sunoco station advertising 100 octane and up and we have a couple of other options in town that are available. This motor would be in a weekend type cruiser and not a weekend warrior. Just getting my feet wet and realizing all my old go fast trick parts can't match up to the newer stuff out there. After reading the link on the Vortec head it makes my old camel humps just some shop art. Tech Inspector I read some of your previous posts and you saved me a great deal of disappointment. I had a brand new set of flat top pistons I was going to use, but after reading one of the topics I discovered that they were the 1.54 compression height piston and not good for mild build ups. Those went down the road, and I thank you for that tip. Thanks for the advice and as I begin to build this up I will be back for more info!
 
#7 · (Edited)
They not only out flow but also out burn the older heads. The L31 Vortec used two castings 12558062 which you have uses induction hardened exhaust valve seats for unleaded fuel. The other casting is 10239906 which uses hard seat inserts on the exhaust side otherwise these two castings are the same.

All of these came with self guiding rockers on press-in studs, the conversion to screw in studs would still require self guiding rockers unless there are sheetmetal guides under the studs in which case they can use the older unguided rocker.

The most common issue with these heads is clearance of the bottom of the spring retainer to the top of the guide oil seal. The guides of this head are pretty high when the stem seal is fitted this restricts max lift to .460 to .470 inch. The most common way around this is to tool the guide lower to gain sufficient clearance. The valve springs are 1.25 inch in diameter which is too small for very radical cams. The safest way to deal with this is the use of beehive or conical type valve springs as the with the raised intake port enlarging the spring seat can easily cut into the port roof. The beehive or conical spring use a smaller diameter retainer which also provides some relief with the guide/oil seal to retainer clearance.

Keep in mind that these heads were for a roller cammed engine that uses a shorter 7.2 inch push rod, when they are used with a flat tappet cammed engine you need to go back to those longer push rods. The average kid at the parts store probably doesn't know that so if he looks these up by year or type of head the short push rod is what he'll find, so you have to know that the push rod lenght goes with the type cam not the type head.

The valves of this head are the same 1.94 by 1.5 Chevy is so fond of. Depending on cam and compression these heads are a 20 to 50 horsepower bolt on. They have very good midlift flow but run flat over .5 inch so going that much or beyond with the lift is of little value without porting them. They very much respond to a 30 degree back cut on the valve's seat, both intake and exhaust, this is very effective on a long duration cam that lifts from .45 to .5 inch at the valve. A split duration cam is also of value as the exhaust flow didn't improve compared to the intake so that side can use a little extra blow down time moreso than extra lift.

The chamber burns fast compared to previous heads, you'll find its happiest with total spark lead of 34 to 36 degrees. The chamber is very detonation resistant compared to earlier chambers many guys run 9.5 or a little more with a squish/quench clearance of .040 to .035 inch. Flat tops or D dish pistons work best compared to the factory round dish pistons because those have too much of their squish/quench surface contribution too far from the head to be effective.

Have them checked for cracks, they don't like to be overheated, if these are used heads and have been overheated the chances of cracking is super high. They also like 4 corner coolant return, there are kits that make this quite easy to install. A pair of fittings on the rear of the manifold over the coolant return opening of the head that can be connected to the intake's forward return before the thermostat. Or they can be plumbed into the heater/bypass circuit. This prevents coolant vapor bubbles from collecting above the rear cylinders causing them to run hotter than desired. This is almost as good for power as the 4/7 timing swap without the cost of the cam, your valves and piston on number 7 will thank you.

Bogie
 
#8 ·
Ok first how long is the valveguide supposed to come up out of the head? I am wondering since there are already screw in studs I wonder if they had been turned down. Since it has screw in studs but no guide plates can I add guide plates so I can use a conventional roller rocker. I don't plan on going any bigger on the Crane 278HMV. It's like .465 intake and .494 exhaust. I like the beehive spring and planned on that being part of the assembly.
 
#9 ·
Guideplates can only be used with screw-in studs if the stud boss has been milled down enough to accommodate the added thickness of the guideplate. If not machined for the guidwplate it will put the rocker stud too high, the radius of the stud near the wrench hex will interfere with the bottom of the rocker arm

A good picture of your bare head in the velveguide top/rocker stud area would be worth 1000 words, many of use here at HRodders can tell in one look what has been machined and what hasn't
 
#11 ·
I will post pictures of them tonight. I plan on using these heads on a 355 with the Crane 278 HMV cam. The bottom end will be SRP flat tops 0 decked and 5.7 Oliver rods with the good steel stock crankshaft. I don't plan on this being a world beater or drag race motor, I have a 1964 Impala station wagon I am putting together and want a solid motor with enough cam to turn heads. The part I may change on the wagon is the 3.73 gears in the rear end. And I want to thank everyone for the great response's to my questions. I have been around racing all my life, but took a break from it when my 3 kids came into this world. They are now getting older and enjoy cars like I do. I am getting up to speed on the modern performance parts.
 
#12 ·
Have you ready got the Oliver rods, and that is why you are using them??
Same deal with the SRP's??

I ask because there are a bunch of lower cost alternatives that would be more than strong enough for your modest intentions, the Oliver's are like using Atomic weapons to wipe out an anthill...total overkill!! LOL.

With the weight of the wagon, a 383 stroker would be a better deal if you don't already have the 350 rotating assembly.

You could likely sell the Olivers and pay for an entire 383 rotating assembly.
 
#13 ·
This is all stuff I had and I agree it is overkill I just wanted it to be solid. A 383 is probably a better option I agree.

I had 3 sets of camel hump heads and I was going to use one of them, but after reading on here about the Vortec heads and that they were better heads in all areas I found this set of 062's and wanted to try them. The only expense I will have in these heads are the hardware (Valves, springs,etc..).
 
#20 ·
The valve guides have been cut down a bunch, looks like a lot more than needed actually, and have also been cut on the diameter for an aftermarket positive seal. Stock guide boss would be about 5/8" tall and almost 3/4" diameter.

I'm guessing the guides are going to have to be replaced or at least bronze linered, unless the pic just makes the head look rustier and worn more than it is.

Looks like the spring pockets have been cut for larger than stock springs also., stock pocket is only 1.270" or so.

Rocker stud bosses have been cut, looks like far enough to also include the thickness of guideplates.
 
#23 ·
. Can't make out most of it, but middle one is a date of 08/27/97... none of it is particularly important... just need the casting number... that shows whether induction hardened or added exhaust seats...


. If added exhaust seats, there may be some lip around them to take out for better flow...
 
#26 ·
Even tho the 906's were the only casting to receive the hardened inserts,not all 906's had them.Only 906's used in heavy duty applications such as 3/4 ton & 1 ton trucks.906's used in 1/2 tons & light duty applications were exactly the same as an 062.I'm sure some of the HD 906's made their way onto light duty engines tho.The only realiable way to say for sure is to inspect the head.
 
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