[Slimpikins]

I would like to know the what the pros and cons are on vortec heads. I recently fell upon a set of 062 heads.
I know I need to have the guides machined to handle up to .550" lift, and the spring area has to be machined to handle doble springs. If I use beehive springs from Comp can I get away from some of the machine work? I also know that these heads stop flowing after about .550" lift, so I decided to go with a Comp 276/284 roller with .502/.510 lift+1.6/1 roller rockers, and It keeps me streetable with 13" of vaccume and a powerband of 1900-5600 RPM.
What compression ratios do I need for this cam and head selection? I know that these heads don't require as much timing. Why???
Just doing some homework. Thanks.

[NXS]

The reason is because they allow the fuel to atomize better, the castings are "cleaner" and the combustion chambers are shaped differently. Put simply they are more efficient than older heads and allow for a faster burn. The downside is they are iron.
This is a good read:
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[38Chevy3WCoupe]

There is also a pretty good article in the March 2006 issue of Street Rodder magazine.

[GoneNova/406]

there is an excellant article in chevy high perf. magazine from june last yr. about all new vortec heads.they are cheap and flow lots of air.go to chevyhighperformance.com and then to blue thunder 355.

[DoubleVision]

Pros: High Flow 170cc runners, 64cc heart shaped chambers that unshrouds the intake valve and are more efficient.
Cons: light, run them hot once and there cracked.

[383MontecarloSS]

Originally Posted by DoubleVision

Pros: High Flow 170cc runners, 64cc heart shaped chambers that unshrouds the intake valve and are more efficient.
Cons: light, run them hot once and there cracked.

Agreed..other than the running hot part. I would not let this scare you away. I reached tempuratures of 220 and nothing bad ever happened.

[curtis73]

I've never personally used any, but if you look at the numbers they get incredible flow from modest port sizes. Lots of air, lots of velocity, yummy recipe to me.

I think their two main downsides are 1) the requirement to machine them for higher lift and 2) the "special" intake bolt angle that doesn't allow you to use old style intakes. Not a big deal if you're going to buy one anyway, but they're not as common at the swap meets.

I've heard of guys hogging out the bolt holes on an old intake so they could bolt it on, but I can't imagine that being ideal or long-term

[Hippie]

Originally Posted by curtis73

I've heard of guys hogging out the bolt holes on an old intake so they could bolt it on, but I can't imagine that being ideal or long-term

The intake ports on the Vortecs are a lot taller, most old style intakes won't even cover the port without adding some material to the manifold. Used Edelbrock and GMPP Vortec intakes are starting to show up more frequently on eBay. Weiand has just released a Vortec intake too.

[NAIRB]

Stock vortec heads can be drilled and tapped for standard intake manifold mounting.

Hippie is correct, there will be a port mis-match, but the mismatch is the proper type where the intake aperature on the manifold is shorter than then one on the cylinder head. Making the port aperature on the cylinder head wide enough and making the heighth on the intake taller will work well as long as the intake opening is not quite as wide as the head is and not quite as tall as the head is.

Vortec heads are excellent but they are lightweight and crackprone.

Racing Head Service now has the rights to the duplicate Vortec head and it is much heavier. (Over 8 lbs of extra iron per head), they are now my preferred choice to use and they come with screw in studs too.

[Hippie]

Originally Posted by NAIRB

Racing Head Service now has the rights to the duplicate Vortec head and it is much heavier. and they come with screw in studs too.

That's good to know.

[Slimpikins]

Im going to use an Edlebrock Intake so the intake clearence problem is solved. My next question is what is meant by the term "fast burn"?
What kind of roller tip rockers do I need? Self-Align or regular? Whats the difference?
Thanks for the help.

[johnsongrass1]

Fast Burn: A term coined to mean more effiecient chamber then previous designs.

You'll need self alining unless you convert to use plates style studs.

Self aligning have a groove machined into the roll tip so the rocker stay's on the valve stem.

[DoubleVision]

I have vortec heads on the engine I just built but haven`t dropped in yet, Still have to get finished rewiring the car and doing some painting, weather got back cold on me so things are stalled. I don`t worry about 220 degree temps, my sisters 98 tahoe runs this temp with vortec heads with no problems, but we have a set that was run 260 and there cracked. unusual part about the cracked vortec heads we have are they have "hencho en mexico" stamped on them so they were made in mexico, haven`t seen another like them, the date code also says "D 6 4" april 6th, but I`m thinking the 4 is 2004, since as far as I know the vortec heads weren`t released until 1996. I didn`t know GM was casting the replacement heads in mexico, but it don`t surprise me either. For my engine I`ve got a new aluminum water pump, thermo clutch fan, new 180 high flow thermostat, radiators new, hoses are new, I`m doing everything I can to keep them below the 190 temp mark just to keep it on the safe side, as BOBCRMAN said to me "keep them cool!!!"

[johnsongrass1]

the 043 bowtie vortec head is 8 pounds heavier and doesn't crack. With the revised seat grinding technique they flow 263@700 lift.