Are the Vortec heads EXACTLY the same as the ones that came on truck engines beginning in '96? If they are, what models and years could have the Vortec engine? How do I recognize a Vortec head? Thanks for all help.

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Mike
formerly known as gotapileof70Malibu
'70 Malibu
'70 Malibu convertible
North Vernon, IN

1 Yes,

2 96 to 98 350 engines in trucks/suburbans/vans

3 odd intake bolt configuration, you cant miss

Why buy used?They are asking more at the junk yard than you can get a new set for.You can go to your local dealer and order a set, complete, for @ $205 each, last time I checked.The intake is more though, around $250 for it.

The Edelbrock performer intakes run about $150 and the RPM is about $175. One thing to think about is how big of a cam your going to run because the springs on them will only take about .460-.470 lift. Like 68 siad the intake bolt pattern is differnt its like a ford where the bolts go strait down instaed of on a 45. Also there are just 8 bolts instead of 12. Just call a local chevy dealer and pick up a new set you should be able to find some for $425 or so. Also keep in mind that they use the selfalighning rocker arms for older SBC's rocks won't work.

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JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports (http://www.angelfire.com/co/KellyMotorsports)

They were first used on the '96 pick up RPO L31 w/fuel injection. Intake & exhaust are simular to the Corvette 350 LT1 heads. They flow better than the Bow Tie heads but aren't as durable. The 8 bolt intake pattern is different than the earleir 12 bolt design. You can convert them by using a GM intake manifold gskt PN 10148096, marking the 6 new bolt locations & drilling holes for 3/8 bolts, or use manifold PN 12366573.
I thought the only manifold Edlebrock had for the Vortec was the RPM??? I know the 'Air-Gap' isn't available yet.
The new GM heads are very competitivly priced, especially through Sallee-Chevrolet
www.sallee-chevrolet.com (http://www.sallee-chevrolet.com) ask for Larry.
FYI...The bolts point straight down rather than at an angle.
Good Luck

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Lowered '67 Elcamino
ZZ430 eng / 4L60E trans
"Canyon Carver"

Susp: Neg. Roll

Cardiac, they make the standard performer, RPM, Victor Jr.2barrel and Super Victor for the Vortec heads.

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JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports (http://www.angelfire.com/co/KellyMotorsports)

Are these vortec heads cast or aluminum???

cast

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Mike
formerly known as gotapileof70Malibu
'70 Malibu
'70 Malibu convertible
North Vernon, IN

There is an aluminum version of this head as well.

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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette

The Vortec is nearly an iron version of the aluminum L98 Corvette head, but it produces better high end numbers while losing very little on the low end.

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Mike
formerly known as gotapileof70Malibu
'70 Malibu
'70 Malibu convertible
see the ragtop at:
http://genxrodsandcustoms.8m.com/mike.html
North Vernon, IN

I believe that the Vortec heads use the aluminum LT1 head's basic port design. They are very different from the the L98 heads.

i am running a mild 350 4 bolt main with a stroker crank, stock heads, and am trying to decide which heads to go with. i have heard alot about the new vortec heads, and am wondering how the would work, of course with porting, and gasket matching. i realize i will need a new intake, but the fewer bolts have me really wodering if the will hold up.

Everything I've been told is DON'T port them. I guess you actually lose performance when you port them. I have also heard that they respond well to polishing the combustion chamber and runners. My .02

Don't port, just polish the runner a little in the rough spots, and there is a rough ridge right on the radius of the exhaust. Directly under the exhaust valve. Blend this a little , just to smooth it out. This is supposed to improve flow up to about 75%.I just pulled 2 valves out of my new set, and it isn't much of a ridge at all, just touch it up a little, and bolt it all back together.

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

click here and Read what BillK posted (http://www.chevelles.com/forum/Forum1/HTML/003100.html) about the heads.

[This message has been edited by 64elcamino (edited 04-21-2000).]

I just bought a set for $75 complete, so I will take a chance on them and see how durable they are. They are extremely thin though. That was the first thing I noticed.

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

My bro & I built a 355 with Vortecs. They required quite a bit of attention, but the car hauls ass. http://www.iquest.net/~harold2/vortec.html is a page with all the information you need to build an engine with them.

thanks all for the info on the vortec heads, they sound to good to be true, and like the saying goes, if it sounds to good to be true it probobly isnt true, looks like it will be the iron eagles for my ride, built motot for torque and dependability, and i dont want the heads to let me down, god knows these stocks ones sure have..CHEVIES forever!!

I've read a great number of people question the reliability of the Vortec head. Chevrolet and GMC trucks have been built by the millions with these heads. I stopped at the local Chevrolet dealer the other day to talk to them about replacing the throttle body on my '00 Silverado and asked about cracked heads on the Vortec powered trucks. THEY HAD NEVER REPLACED ONE except in conjuction with a complete engine replacement, and they sell lotsa trucks.

My question is: Who on this forum has "first person" knowledge of this problem?

I've been paying close attention to *any* discussion about Vortec heads, because I've been thinking about using them for a while.
I can say with a fair degree of certainty that, since this was brought up a couple months ago, NOONE has stepped forward with firsthand knowledge that these are cheap, thin castings and are prone to cracking in high performance applications. None.

-Brian

Ditto Vitriol,I agree. Notice my post above. I have been following also. I got lucky, and I am supposed to get a call back when others ones are available. As for now, I bought a roller 305 out of a Trans Am, and plan on finding a '86-up model 350 block, and building up a roller 355 w/ the same $75 Vortec heads. Econo performance! http://www.chevelles.com/forum/biggrin.gif

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

[This message has been edited by Doug Garland (edited 04-25-2000).]

stroker questions. isnt a small block 350 block with a 400 crank called a stroker?also isnt a 400 block with a 350 crank called a destroker? ihave a buddy who does circle track motors, and he always races 400 block with 350 crank, says it winds faster. thanks.

just wanted to post new info about my son and my vehicles..
if i changed the exhaust on my 99 pontiac, would it void the warranty, factory and/or
extended?

also can buy from scoggin-dickey chevy in texas a vortec head, brand new already altered to fit early intakes, i.e. non vortec intakes.article in chevy high performance are about them building up a small block with vortec heads.384 dyno hp on a new 350, comp cams268 xtreme energy cam, roller tipped lifters, edelbrock perf rpm, holley 750 carb,hooker headers , and hooker turbo mufflers, sopposedly with stock bottom end.love that extreme energy dual pattern cam. got one in my truck.

I believe that GM Performance started the rumor that the L31 Vortec heads are weak themselves. The catalog description includes the following: "This head with compatible valves flows more air than bow tie head P/N 10134392, but the casting may not be as durable." Not sure why they bothered to say that, but it is a direct comparison to the bow tie head, no other. I have never heard of anyone having durability problems with these heads.

Blazer- I think one reason they said that was because there isn't much material around the ports. So theres not much that can be done to modify them, they don't want someone buying them for a race car expecting to work them. But in the same hand they want to point out to those people who don't want to have to do any port work, and that they are better right out of the box.

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JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports (http://www.angelfire.com/co/KellyMotorsports)

[This message has been edited by L6571SS (edited 04-27-2000).]

I have been using the vortecs on my 355 in a 3600 pound 76 camaro for two years now without any problems. The heads are bowl blended and have better valve springs but are otherwise unmodified. the motor has seen the six grand plus runs numerous times w/o any problems or cracks. i just checked them recently when I pulled them to install thinner head gaskets. I am running the 268 extreme energy cam and a 3.42 gear and have run a best of 13.22 @102.97 with a 700 double pumper and a 2500 stall. I think these heads are great and I have had no problems. Lots of bang for the buck. By the way, I had much better luck with the double pumper than the 750 vacuum sec.I plan to run a 3.90 gear with 28 inch tall tires and the super victor manifold next year. hope for mid-high 12's. not bad for heads I got for $200 used.

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I can't find these heads anywhere for anything near that price! Arg! I called around to tons of boneyards and all but one didn't know what the heck I was talking about (1 out of 5).

Enough is enough. Here is what I know about vortec heads. Intake flow comparable to LT4 heads. Exhaust flow comparable to LT4 up to .300 lift then lags just slightly behind (not enough to notice.) Max valve lift is .460 to .480 (range is due to production line machining/casting variance, check for clearance on anything over .460". Stock vortecs, modified only for valve lift will make 410-420HP on a high compression shortblock 355 (typical circle track engine.) Vortecs require a Vortec style 8 bolt intake, they should not be modified for older 12 bolt style intakes, not enough section thickness for proper bolt retention at the location of the center bolts. Also, most intakes can't be ported enough to match the raised intake ports on the vortecs. Durability of the vortecs is not a concern, the reference in the catalog is for the 8000 rpm,13 to 1 circle track guys. These heads have been installed on millions of trucks and thousands of hot rods. We sold 8700 of these in 1999 and already exceeded that number this year. We have never warranteed one sold for high performance applications. If you buy vortecs, keep your reciept, if it breaks (and it would be the first one) I'll replace it. Just contact your dealer, they know how to get to me.
Oh, and by the way, there are no true fast burn aftermarket heads...only from GM, we are at least 10 years ahead of the aftermarket in combustion chamber design.
Regarding porting, a little clean-up on the vortecs is OK, but if you dramatically open up the ports you lose the venturi effect in the intakes that makes them flow and perform as well as they do.
The vortec head was designed by the same guys that did the LT1 and LT4, one of which was a former GM winston cup head engineer for over 10 years, he's back at GM Racing doing race heads again.There is no head for a 23 degree smallblock which is more technologically advanced in terms of flow management and combustion management than the vortec. Have a great day and by the way we invented the small block, who do you think knows it better than us?

Just to put my two cents in here, I own a small repair shop in truck country (Montana) where 70% of my repairs are on trucks and the only trend I see on 96-98 Chevy trucks concerning these heads is the intake gaskets themselves. I have had to replace several sets already due to coolant leaks from the rear. This is not any worse than the 88-95 trucks although they seem to be popping up a little earlier in mileage. I have seen them go in as little as 35,000 miles. I do think with proper coolant changes and redesigned gaskets there should not be too many problems. I haven't had one come back yet! (fingers crossed!)
Todd

Gary, if you're still looking at this thread, could you please comment on the importance of combustion chamber design vs. port design with respect to their relative importance to a performance engine?

Heads that flow well have been around for years, but I've only been hearing about combustion chambers over the last few years; is combustion chamber design now the most fruitful place to find additional performance in a cylinder head?

As always I remain...

Big O Dave

Johan, sounds like a strong mouse. If your gonna bust open the rear, why not toss in a 4.11? I had a 10:1 355 in my chevelle (3100lbs)w/ 28.5x10.5 slicks, 4500 stall,4.11s, and it ran 11.70s @ 113 mph. My cam was a crane 280deg,.540 lift mechanical. you will like those 4.11s w/ the 28.5 tires...my trap RPMs were around 5800-6000. Is it race only or street? 4.11s are about the best compromise for both. Plus the lower gear will hump it out of the hole quicker, especially if you decided on a looser converter, but converter selection depends on the cam your running. My cam's range was 4500-7500. (bracket race only, streetability no concern, but i could have muffled it and drove it by the beach) If it's race only, with some monetary gifts (yeah,right) I'd use your mill,w/ a 4500 stall converter, manual valve body in the trans, 4.56 gears,and 28.5x10.5 slicks. Trap RPMs W/ 4.56s may be alittle higher, like 6500, but thats well within safe limits for a smallblock. Then, drive it like you stole it!! You'd be in the 11s easy http://www.chevelles.com/forum/smile.gif >>>Dave

What was the name of that Ass Hole who started this post almost a year ago? I bet he still doesn't have a set of heads. He probably hasn't even had the block bored and hot tanked yet because the one shop in his area charges an arm and a leg!

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Mike A.
North Vernon, IN
'70 Malibu
'70 Malibu convertible (http://genxrodsandcustoms.8m.com/mike.html)

Are the Fast Burn heads just an aluminum version of the Vortec, or do they have different port/combustion chamber profiles? I know the Fast Burns use "as cast porting" technology, but do the Vortecs?

If I remember correctly, the Fast Burns flowed about 30 or 40 cfm more than my old Dart Sportsmans which were bowl blended.

From What Bill K described as the very thin deck surface, I would be afraid to use the Vortecs on a high compression bracket motor.

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Todd Geisler
79 Malibu
11.16@125.8mph
Malibu Muscle
http://www.MalibuMuscle.cjb.net

A saying in Politics
"Repeat a lie 80 times, and it becomes the truth."

It's kinda like the this "thin" deck problem. A year long thread and nobody knows lst hand about a failure. Thousands of hotroders and circle track racers using them. Millions of trucks with them. No one knows of failures, but people still warning about them. Repeating what they heard or read, from people repeating what they heard or read. Todd, why do you feel that your bracket car will put more stress on them than a truck pulling 12,000# up a 20% grade for 10 minutes without breathing?

The combustion chamber on the Fastburn alloy heads is way different than anything else on the market to date. The intake and exhaust ports look very good as produced, and examination of flow data is impressive as well. They ARE NOT just an aluminum vortec.

Maybe you got me there Mr. Greybeard. Just call me ignorant...Racer1320 probably does http://www.chevelles.com/forum/smile.gif

I have a habit of making poor engine decisions. At least I have nobody to blame but myself.

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Todd Geisler
79 Malibu
11.16@125.8mph
Malibu Muscle
http://www.MalibuMuscle.cjb.net

Todd,

Please excuse the "tone" of my post. I'd just had and interesting conversation on the phone, and I think it effected my wording.

The facts are the same, but please excuse how I said it.

Hey Big O Dave, how's the tire biz? Here is the short version of the importance of combustion chamber design. First some assumptions, air fuel ratio is right, meaning enough present oxegen to support total combustion of the fuel. Second, forget about the "crevice", the area above the top ring between piston and cylinder wall where the fuel will not burn efficiently. Third, assume flat top piston, best design, promotes most rapid flame travel. Now compare a theoretical combustion chamber with piston at tdc and no air movement. This of coarse would never happen, but bare with me. To burn the fuel would require maybe 60 degrees of timing lead, because you have only the close proximity of the fuel atoms to spread the burn from the plug accross the area of the chamber. This would mean your engine would "fight" against building combustion pressure as piston approached tdc. Very inefficient. "old fashioned" combustion chambers are more desireable than our theoretical case because they induce turbulence. The turbulence speeds the spread of the burn, but in a random and uncontrollable fashion. Requireing maybe 34-38 degrees ignition timing lead. Better, but still not great. This is all heads built prior to the early 90's. And, most aftermarket heads, which are "tweaked" copies of "old fashioned" production heads. Now consider the Vortec head with its predictable and repeatable swirll patterns. Faster burn rate than our previous examples, requireing even less timing lead, about 30-32 degrees, therefore engine has to fight the mounting pressure less than the previous examples. This means more power available to put to the ground, or up in smoke I guess. The theoretical ideal engine would have such a fast burn rate that total combustion would happen at the moment of ignition. Then you could run 0 or 1 degree timing lead. Don't hold your breath waiting for this to be reality, the laws of physics aren't cooperating with us on that one. Make sense to ya?
Regarding port design, "total area under the curve" is most important. Most buy heads based on peak claimed flow at some valve lift (ie. 250 cfm at .600" lift.) But more important than that is flow at all levels and particularly low lift flow. If you chart your flow at all valve lifts from open to close it looks like a bell graph (the line will be shaped like a bell). The fatter the bell the better. A narrow pointy bell is no good. Also, you need efficient flow management, that is laminar flow without turbulence in the ports. Turbulence creates "voids" or low pressure pockets that mean your port will not pass as much air as the same port witout turbulence would. Laminar flow takes the air through the port intact, essentially fills the port with quality air without "voids". Another thing to consider is velocity and momentum. Air and fuel have mass, so they can be accelerated and will have momentum. The Vortec head uses a venturi built into the port shape to accelerate the air/fuel after it makes the turn toward the valve. This creates low pressure behind it, drawing more air/fuel. And it gives the air fuel high velocity and momentum so that it has a lot of energy when it hits the back side of the open valve, because at this point it has to be redirected and loses energy as it's redirected.
So, bottom line is best high velocity laminar flow at all valve lifts with a controlled high swirll chamber, combined with a flat top piston. Currently, no aftermarket head can begin to compare with the Vortec, even the Fast Burn lags a little behind in the quality of these characteristics.

Wow! That is a tough act to follow. Re the fraility of the vortec head, I put a supercharger on the old lady's stock 350 Suburban and we have driven the hell outta it for the last 41,000 miles without a whimper. It has about 67K on the clock now. I am sure YMMV, but from my perspective, they are tough

Thanks, Gary. Excellent explanation! There are TONS of us car-techies out here CRAVING info like that, and it's even better straight from the "horse's mouth."

Speaking of mouths, you still haven't shared your "goat taco" story. If I remember right, you were down in Mexico, visiting the engine plant when...

Has anyone used nitrous with these heads? Does anyone have a set of these heads for sale? What about some dyno numbers? Thanks