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GM Performance Heads: New large port vortech sbc heads?

zackm58941

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Joined
Jan 20, 2004
Messages
67
Location
Rochester, New York
Corvette
1980 Corvette
Hi again, I'm starting to look for a good set of performance heads for my 1980 l-48. I was on Jegs.com and saw these, http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=427383&prmenbr=361. Would these be over kill on the stock engine? Right now I want to do heads, cam, intake and carb with the stock engine, later on I will put in a short block but for right now I just wanna have a little more fun with the car. I've looked at the original vortech heads for a while now, http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=4242&prmenbr=361, and they look like a good bargane. Which of these 2 heads is the better buy?

Large port Vortech Heads

- 2.00'' hollow stem intake valve
-1.55'' sodium filled exhaust valves
-The deck surface is .450'' with 65 cc combustion chambers
-206 cc intake runners and 77 cc exhaust ports
-Can handle up to .530" lift cam

Regular Vortech Heads:

-1.94'' intake valves
-1.50'' exhaust valves
-170 cc intake runners
-64 cc combustion chamber
-.475" max lifting cam

For the regular votech heads I see that you need to buy self alighning rocker arms, what exactly are these? Do I need different length pushrods? For any one who has put these heads on before, I would greatly appreciate any input to how you like them, how they fit up with the stock accesory's (alternator bracket + A/C bracket). I'm guessing the static compression ratio would be around 9.0:1 or so? Just estimating, what would the hp and tq for the engine be with these heads, a decent cam, intake, carb and long tube headers w/ no cats? Sorry for all these questions, I would appreciate any help guys/gals!

Thanks !!!!
Zack
 

80convertible

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Joined
Jan 26, 2001
Messages
416
Location
Asheville, NC
Corvette
1973 converted to 1980 custom convertible
I purchased a set of rebuilt vortec heads about 4 years ago. I installed them right on to my stock 350 that has not been rebuilt that I know of. They install just like any other chevy heads with the exception of the vortec specific intake and center bolt valve covers. I had not problems reinstalling my accessory brackets and I also have headers. I can't give any specific before and after performance numbers but they run very well. I still need to change my cam to match the flow characteristics of the vortec heads. I'm not realizing the full power potential with the current cam I have. Vortec heads on a mild 350 are worth well over 300hp and more.

Stock vortec head springs are not designed for high lift cams. Also, they use self aligning rocker arms which have a recess in the middle of the rocker to keep the rocker arms centered to the valves. Vortec heads do not use guide plates. I purchased my heads used and the price I paid included the rocker arms and valve covers. There are lots of used vortec heads for sale either thru ebay or the other forums such as the first and second gen camaro forums.
 

zackm58941

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Joined
Jan 20, 2004
Messages
67
Location
Rochester, New York
Corvette
1980 Corvette
Thanks for the input 80covertible!!! After pricing everything thing out with the large port heads it was like $2,000! Ouch, thats a little too much for all that, they really get you by getting their specific bolts, intake and so on... They look like awesome heads and probably would make my car run so good. I wounder how much power loss I wound take by going to the regular vortech heads vs the large port ones? What do you think the overall compression ratio would be with these heads? Thanks for all your time everyone!

Zack
 

KANE

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Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
zackm58941 said:
I wounder how much power loss I wound take by going to the regular vortech heads vs the large port ones?

I just finished a Car Craft magazine that compared the two sizes. I think they were about even in terms of performance (flow). Smaller combustion chambers will mean higher compression. Detonation may be an issue too.

Don't forget to take your piston to valve clearance into consideration. Oh, then intakes. Make sure you match the intake to the heads. It would be terrible to spend a load of money, then have to spend more, just to get things to match.
 

zackm58941

Well-known member
Joined
Jan 20, 2004
Messages
67
Location
Rochester, New York
Corvette
1980 Corvette
Thanks DarkShark78! Sounds like a good magazine article, they wouldnt have that one online would they? The stock compression on my enigne is 8.5:1. I dont know the stock head size cc's so cant really estimate what the compression would be bumped up to, anyone know this?

Thanks,
Zack
 
D

dfw81shark

Guest
zackm58941 said:
Thanks DarkShark78! Sounds like a good magazine article, they wouldnt have that one online would they? The stock compression on my enigne is 8.5:1. I dont know the stock head size cc's so cant really estimate what the compression would be bumped up to, anyone know this?

Thanks,
Zack


I think this is the article he is referring to.
http://chevyhiperformance.com/techarticles/148_0507_vortec/
I subscribe to both magazines and I know they are easy to confuse with each other. The article is a Vortec street comparo. What makes me mad is that they tested the Edelbrock E-tec 170, but not the 200, which is what I have. It is hard to find comparison numbers for the 200s. I went with Edelbrock because at the time, I didn't want to worry about modifying the heads to get them to work. These heads are bolt-on with the vortec intake. Edelbrock's manuals suck, but otherwise I think everything I have is good equipment. I have about $3000 into the upgrade so far. But what I was getting at in my rant was that nobody tests these heads even though they are something like $40 more than the 170's. They claim they aren't street heads. Oh well.
 
Joined
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Messages
7,246
Location
Washington, Michigan
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'67 Marina Blue Convertible
zackm58941 said:
Thanks DarkShark78! Sounds like a good magazine article, they wouldnt have that one online would they? The stock compression on my enigne is 8.5:1. I dont know the stock head size cc's so cant really estimate what the compression would be bumped up to, anyone know this?

Thanks,
Zack

Your stock 1980 heads (462624) have 75.47cc chambers.
:beer
 

KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
dfw81shark said:
I think this is the article he is referring to.
http://chevyhiperformance.com/techarticles/148_0507_vortec/
I subscribe to both magazines and I know they are easy to confuse with each other.

Ooops. I get Car Craft, Hot Rodding, Super Chevy, and GM High Performance (?)... so, yeah, it IS easy to get condused which magazine has which article. Even worse- I think Peterson owns a couple of them- and they print similar stories! Thanks for posting the right one!
 

zackm58941

Well-known member
Joined
Jan 20, 2004
Messages
67
Location
Rochester, New York
Corvette
1980 Corvette
This is awesome, so much good information from everyone! Seeing that the stock combustion size is 75.47cc's, would it be safe to say that with the regular vortech's heads 64cc chamber would make the static compression ratio around 10:1? I'm not too sure, a new cam will deffinetly change that too but more likely at lower rpm's right? I would like to keep the CR at about 9.5:1 or a little less, what thickness head gasket would help me do this, anyone know the stock thickness?? Thanks for all the help everyone, this has given me so much to think about and I know its a lot of me to ask too.

Thanks,
Zack
 

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