vortec spring upgrade?


Staff member
"Ok, GRUMPY,? i have stock vortec heads, and i am trying to run this cam below with stock vortec heads,

The L31 Vortec comes in two different casting numbers, 10239906 (#906) or 12558062 (#062). Originally, the stock #906 casting head was available in two versions. One version had an Inconel exhaust seat with single angle valve grind and was available on 1 ton trucks. The other version was the traditional three angle valve grind. Other than that, the #906 is the same as the #062 head.
GM Performance Parts Bowtie Vortecs are offered in “small port” (#25534351), which has 185cc intake ports/65cc exhaust ports, or the “large port” (#25534445), which features 225cc intake ports/77cc exhaust ports. Both GM factory and GM Performance Parts Vortecs come with 1.94 intake/1.50 exhaust valves. According to the engineers at GM, “Stepping them up to 2.02 valves doesn’t help them any, so it’s not recommended. The port was designed to match the 1.94 valves. With the Vortec flow velocity,
IVE read you can upgrade vortec springs with these, springs below to gain more clearance,
The main problem with the stock vortec heads as many people know is the lift clearance restriction of about .480, If you have the heads off the engine, I see most people would recommend having the correct machining of the valve guide done and have screw in studs installed. However, Ive heard you can make these heads work with larger lift cams without removing the heads. Swapping the valve springs seems simple enough.

but read further, increased valve spring load rates generally require screw in rocker studs and in some cases push rod guide plates, if you change the installed height you might require a different rocker or push rod.

IVE SEEN KITS that say they allow .550 lift on stock vortec heads
but keep in mind upgrading springs does not change the valve length or if you reuse stock spring retainers the installed spring height or distance between the valve spring retainer and valve seal, so unless you machine the valve guides or change retainers and valve seals all the valve spring upgrade can do is potentially increase the spring bind clearance slightly,m thus the use of an offset retainer and springs can be used but moving the valve spring retainer higher on the valve spring to gain clearance can cause other clearance issues, so the proper route is to have the valve guides machined for different seals and use new valve springs to gain clearance

http://www.ebay.com/itm/VORTEC-VALVE-SP ... 4843689115

http://sdparts.com/details/scoggin-dick ... sd1004-1-0 "

http://www.chevyhiperformance.com/techa ... ewall.html

if you do a GOOGLE SEARCH for .600 lift SBC valve springs 1.29" in diam. youll find several options but keep in mind the spring load rates, retainers and valve seals will usually be required and machine work on the valve guides will usually be required for cams with lifts over about .530

NEWER vortec heads require different valve covers that the traditional first gen SBC but there are adapters available to sallow their use, but they cost almost as much or more than many valve covers themselves

http://www.jegs.com/i/JEGS+Performance+ ... 0/10002/-1

while Im sure you can "back alley/ BUBA ENGINEER" the correct clearances , to allow a .540 lift cam to spin without binding,up the valve train, if you swap, in enough new parts and/or modify parts like new spring retainers,valve springs and valve keepers and push rods and rockers your chances of getting the correct spring pressures installed heights and maintaining the correct clearances and valve train geometry is almost non-existent if you don,t machine the stock vortec heads and start measuring and verifying clearances, without machine work your not going to increase the distance between the current valve seals and the valve locking groove so while you could use offset retainers and valve locks to gain clearance you'll need new valve springs and the chances are excellent that the valve train geometry will be wrong without longer valves and push rods or some other mods, the correct route is simply to take the heads to a quality machine shop and have the correct valve seals, shims, springs etc. installed by some one that knows what to check and what they are doing


http://www.customclassictrucks.com/tech ... index.html

http://www.carcraft.com/techarticles/11 ... index.html













keep in mind the intake manifold bolt angles and port shapes and locations are very slightly changed and are different on vortec heads , than on standard heads and some aftermarket heads are designed as a compromise that in theory can be used in either application, but like many compromises thats not always 100% true


standard small port intake on vortec heads, in many cases you can get them modified to fit BUT NOT ALWAYS, as bot intakes and heads vary between manufacturers




above is a very typical machine shop invoice for reconditioning a set of used vortec heads, notice theres $982 plus in charges and theres a great deal more that could easily be required to recondition used heads, now add the rather typical purchase price of at least $200-$400 for a set of clean used vortec heads and you quickly find you could buy better heads for the cost involved
so be aware that just the cost of used or bare heads is not the total cost youll see.

Intake Manifolds For Vortec Heads

2116 Edelbrock Performer
21161 Edelbrock Performer, Polished 2116
5426 Edelbrock C-26 Dual-Quad
7116 Edelbrock Performer RPM
71161 Edelbrock Performer RPM, Polished 71161
2913 Edelbrock Super Victor, Single-Plane
2912 Edelbrock Victor JR. Sportsman 2V Vortec
7516 Edelbrock Performer RPM Air-Gap Vortec
75161 Edelbrock Performer RPM Air-Gap Vortec, Polished 7516
12496820 With EGR, square and spread bore carb mount
12366573 GM RPM Style, Squarebore Carb.
12496821 GM TBI with EGR
12496822 GM Eliminator Vortec Design (Same as Edelbrock P/N 2913)
------ Holley MPI Commander 950, MPFI Fuel Injection Kits.
3507 Edelbrock Performer RPM Pro-Flo EFI .
2516 Edelbrock Performer RPM (Marine application, but allows to bolt on a Quadrajet without an adapter) .

Note: You can view Edelbrock/Vortec intakes here

Intake Gaskets For Vortec Heads

1255 Fel-Pro Intake Gasket
89017465 GM Intake Gasket(old P/N 12529094)
Rocker Arms for Vortec Heads
12495490 GM Rocker Arms, 1.5 Ratio, Stamped Steel, Self-Aligning
12370838 GM Aluminum Roller Rocker, 1.5 Ratio, Self-Aligning
12370839 GM Aluminum Roller Rocker, 1.6 Ratio, Self-Aligning
1417-16 Comp Cams Magnum Roller Rocker, 1.52, Roller Tip, Self-Aligning
1418-16 Comp Cams Magnum Roller Rocker, 1.6, Roller Tip, Self-Aligning
1317-16 Comp Cams Pro Magnum Roller Rocker, 1.52 Ratio, Self-Aligning
1318-16 Comp Cams Pro Magnum Roller Rocker, 1.6 Ratio, Self-Aligning
10751-16 Crane Gold Roller Rocker, 1.5 Ratio, Self-Aligning
10758-16 Crane Gold Roller Rocker, 1.6 Ratio, Self-Aligning
Camshafts For Vortec Heads
There are hundreds of cams suitable for use with the Vortec head.
Example: 12-235-2 Comp Cam Extreme 4 X 4, flat tappet cam, lift I .447”, E .462”, duration @ .050” 210 degrees Int., 218 degrees Exh.

Strong low end and mid range torque. Excellent cam for RV's and pickups when changing to the Vortec heads.

Note: Valve spring change is required if changing to a performance cam.
Valve Springs For Vortec Heads

10309-1 Crane Cams valve spring and retainer kit. Drop-in springs with no machine work needed.
Valve Covers For Vortec Heads
12355350 GM Chrome With Red Bow Tie In Center
24502540 Valve Cover Adapter, converts center bolt to parameter bolt
10046089 Center Bolt Valve Cover Gaskets
Holley custom cast aluminum valve covers with ball-milled top. The rigid 1-piece aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.

Holley custom cast aluminum valve covers with polished flat top. The rigid 1-pc aluminum castings combine strength and light weight in a design that provides a tight gasket seal while also acting to reduce valve train noise.

Mr Gasket, 1987-up SBC, center hold down, baffled. Included: 2 covers, 1 oil fill cap, 2 PCV/breather grommets.

Head Gaskets For Vortec Heads
10105117 GM Composition Head Gasket, 0.028” thick compressed.
12557236 GM Composition Head Gasket, 0.051” thick compressed.
1094 Fel-Pro Head Gasket, 0.015” thick compressed.
Spark Plugs For Vortec Heads

5613611 R44LTS, set of 8
5614210 MR43LTS, set of 8
25164641 #3, Rapidfire style, set of 8
P526S Accel U-Groove “shorty” Double Platinum Header Plugs approximately 3/16" shorter then R44LTS plugs, set of 8
Miscellaneous Parts For Vortec Heads
12495499 GM Head Bolt Kit
12495491 GM Flat Tappet HD Push Rod Kit
12371041 Factory Roller Cam Push Rod Kit
12550027 GM Intake Bolts Set
134-2002 ARP SBC Vortec, Intake Bolt kit. 6-Point Bolts and Washers, Black Oxide, quantity of 8.
434-2002 ARP SBC Vortec, Intake Bolt kit. 6-Point Bolts and Washers, Stainless Steel, quantity of 8.
134-2103 ARP SBC Vortec, Intake Bolt kit. 12-Point Bolts and Washers, Black Oxide, quantity of 8.
434-2102 ARP SBC Vortec, Intake Bolt kit. 12-Point Bolts and Washers, Stainless Steel, quantity of 8.
8032 Edelbrock Universal Throttle Bracket. For SBC Vortec or Edelbrock E-Tec heads.
Bare Vortec Head
12529093 Same as P/N 12558060 except it doesn’t include intake valves, springs, and retainers.
MIKEB said:
On a conventional SBC head with standard length valves and 1.700" installed height, you can gain .035" travel simply by using beehive springs, which use smaller gauge wire. For example, the popular CompCams #981 conventional spring coil binds at 1.150", whereas the #26981 beehive spring coil binds at 1.115".
MIKEB said:
On a Vortec head, the limiting factor is valve guide boss height, so one solution is to use offset locks as mentioned in the posts above. Another solution that will get you more than .035" is to cut down the valve guide boss height and diameter, which can be done at home using a CompCams cutter and a drill press, or even a hand held electric drill.

Below is another Vortec solution that requires no machining. I confess to not knowing spring installed height using the listed retainers and locks with Vortec valves. But, as I recall, the combo gets you >.500" safe lift and higher RPM potential thanks to increased seat pressure. An Internet search will turn up lots of info on this combo. Prices were as of 2014.

LS6/LS2 beehive springs
GM 12499224 (blue)
Set of 16: $61
OD: 1.20”
Spring rate: 375
Installed Height: 90# @ 1.800, 126# @ 1.700
Open Pressure: 295# @ 1.250, 314# @ 1.20”
Max Lift: 0.570"
Top ID: .650”
Top OD: 1.055”

Retainers for this spring ID and Vortec 11/32” valves:
Comp 787-16 retainers: $52
Comp 648-16 locks: $24

the last thing you want is too remove a valve spring and have the valve to drop into the cylinder,
if you use air the crank tends to want to spin the crank to BDC, youll want to verify TDC ,
and make sure the flywheels temporarily prevented from turning fro the TDC position,
Ive used both methods both work, Ive used both with zero issues,
If you use the compressor youll want to keep it at 120 psi and constantly feeding pressurized air to keep the valves held in place,
and theres a small chance the compressor pushes enough moisture to allow water to accumulate in the cylinders,
so be sure you spin the engine with the starter with the spark plugs removed several times before you re-install plugs.
if you use the rope, theres a very low chance that the rope will tangle and form a knot that makes removal difficult

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