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Vortec heads (need to know type of stud)


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http://www.sallee-chevrolet.com/frame.html?/Cylinder_Heads/sbc.html

vortec1.jpg

 

as the standard 170cc port size version comes from chevy they are PRESSED in studs

 

VORTEC CYLINDER HEAD TECHNICAL INFORMATION

Part Number: 12558060

Description: L31 with valves

Material: Cast Iron

Head Bolt Torque: 65 ft./lbs.

Valvespring Seat: 1.300” O.D., 0.850” I.D.

Valve-guide Seals: Viton rubber positive seals, total 0.450” retainer-to-seal clearance Combustion Chamber Volume: 64 cc

Spark Plugs: Straight

Heat Risers: No

Valvesprings: Single wire with damper 1.235” O.D., 0.875” I.D. 75-pound seat pressure @ 1.700” installed height Coil-bind @ 1.150”

Intake Bolt Pattern: Four bolts per side

Rocker Arm Style: Self-Aligning Intake Runner Volume: 170 cc

Valve Diameter: I: 1.94”, E: 1.50”

Casting Numbers: 10239906 and 12558062

Max. Valve Lift: 0.420” which allows 0.030” retainer-to-seal

Rocker Stud: Press-in, 3/8” diameter

Spark-plug Style: 14 mm, ¾ reach, tapered seat

 

 

chevy has just announced NEW versions of the vortec heads which are designed for increased flow and are similat to the FASTBURN heads but the new vortec 206cc heads are CAST IRON

PART # 25534371

theres also a slightly improved 175cc version part# 25534351

 

these new heads are drilled and tapped for both old and new valve cover and both old and vortec style intakes, they have 2.00 intake and 1.55 exhaust valves and 65cc chambers

 

http://chevyhiperformance.com/techarticles/148_0506_thunder/index1.html

 

look 1/3 down the page for flow #s

 

but before you get crazy... look at the DART PLATINUM IRON HEAD FLOW NUMBERS on this same page....a similarly priced aftermarket iron head

 

http://users.erols.com/srweiss/tablehdc.htm#Chevy

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yes and no! removing ones usually easy enough, slide a 1/2 drive deep well,spark plug socket thats about 1/2" shorter than the stud over the stud , drop on a couple 3/8" fender washers,then tighten a rocker nut,on the sockets base, it will suck it right out of the head, getting it back in is not that simple on the engine, off the engine a hydrolic press makes installing a new one easy enought, but DON,T THINK ABOUT BEARING IT IN, youll CRACK THE HEAD or bend the stud, and it won,t be secure anyway,unless you pin it in place, most repair shops,that do replace them on the car pack the new stud in DRY ICE OVER NIGHT THEN WACK THEM INTO PLACE WITH A PLASTIC HAMMER WHILE HOLDING IT ALIGNED WITH PLIERS, personally ID get them all machined for the screw in type

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BTW that having the rocker studs pull loose or having the poly locks come loose is usually and easily ,totally avoided with the use of both screw in rocker studs and a matched stud girdle that clamps to the adjustment rocker nuts

 

 

http://store.summitracing.com/partdetail.asp?autofilter=1&part=ARP%2D134%2D7101&N=700+115&autoview=sku

 

http://store.summitracing.com/partdetail.asp?part=SUM%2D141010&N=700+%2D108204+115&autoview=sku

 

since its reasonably easy and cheap to do its basically a great idea, most machine shops can cut rocker base on the heads and thread the base and install the threaded studs in a day and usually for about $80-$120, not including the studs or guide plates if those are needed.....about this time those aluminum heads with the guide plates, better port design,screw in studs, better springs with more clearance, the far better flow numbers and less weight should start looking like the BARGIN they are!

 

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=78237

 

http://store.summitracing.com/partdetail.asp?autofilter=1&part=TFS%2D30400002&N=700+115&autoview=sku

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