All this talk about vortecs..
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 833
Likes: 4
From: Mexico NY
All this talk about vortecs..
Kind of interesting but this page has flow data for several heads....
http://users.erols.com/srweiss/tablehdc.htm
and all I can see is that 882's are really not that bad of a head.
It seems that the flow results (and desktop dyno results from them)
don't make that large of a difference....
Just my opinion...
flat tops and a cam get you near 290 hp...
is it the torq I'm over looking?
thanks
tim
http://users.erols.com/srweiss/tablehdc.htm
and all I can see is that 882's are really not that bad of a head.
It seems that the flow results (and desktop dyno results from them)
don't make that large of a difference....
Just my opinion...
flat tops and a cam get you near 290 hp...
is it the torq I'm over looking?
thanks
tim
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Tigman, look here for the 882 head spec. http://www.chevytalk.com/tech/engine/SBC_Heads.html
The Vortec have better runners, chamber and 64cc, plus you can buy them all-over like Summitt or SD. http://store.summitracing.com/partde...5&autoview=sku
I plan on this change, 64cc from the 76 may raise my CR to high 8's, better flow. Well___ just planning on some fun and did not want to put $200 in the old heads that are leaking oil.
The Vortec have better runners, chamber and 64cc, plus you can buy them all-over like Summitt or SD. http://store.summitracing.com/partde...5&autoview=sku
I plan on this change, 64cc from the 76 may raise my CR to high 8's, better flow. Well___ just planning on some fun and did not want to put $200 in the old heads that are leaking oil.
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 833
Likes: 4
From: Mexico NY
yeah,
Regardless I going with dart iron eagles (if think work out with the ultra cool machine shop portcitymachine ). but I'm just saying that they don'yt seem THAT bad..........
Regardless I going with dart iron eagles (if think work out with the ultra cool machine shop portcitymachine ). but I'm just saying that they don'yt seem THAT bad..........
Le Mans Master
Joined: Mar 2004
Posts: 7,502
Likes: 1,508
From: Little Rock AR
The 76cc chambers on the 882's are poor for making any compression and the flow numbers posted are from who knows where and what the conditions were. Vortecs are a great deal for a mild street upgrade on an L-48 as they flow great and have modern smaller chambers. If you need to modify them much because of high lift requirements the great deal is still good, just not AS great. If you need bigger springs or bigger ports or just want to keep it looking more "stock" the Vortecs are not a great deal.
I went with the Darts as you have much more performance capabillity built into them "as purchased" and you still have the ability to run the stock 1st generation small block parts/gaskets etc. If you need to modify the Vortecs much at all you will quickly arrive at a price that is close to the Darts which are already fully loaded with the bells and whistles from the get go. Not too bad of a deal at less than $800 for the pair.
-Mark.
I went with the Darts as you have much more performance capabillity built into them "as purchased" and you still have the ability to run the stock 1st generation small block parts/gaskets etc. If you need to modify the Vortecs much at all you will quickly arrive at a price that is close to the Darts which are already fully loaded with the bells and whistles from the get go. Not too bad of a deal at less than $800 for the pair.
-Mark.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
all production vortecs are cast iron ... all of em came on lite-med truck motors.
some aftermarket versions of vortec are Al.
and yes ... a small cam, flattops & 76cc production iron heads will easily make 290hp & lotsa tq.
points of reference:
GMPP 290 fwhp crate p/n 12499529 does it w/ dish, plain 76cc iron heads & a small cam.
Production 1971 L48 270 fwhp w/ dish, plain 76cc iron heads & VERY small cam.
some aftermarket versions of vortec are Al.
and yes ... a small cam, flattops & 76cc production iron heads will easily make 290hp & lotsa tq.
points of reference:
GMPP 290 fwhp crate p/n 12499529 does it w/ dish, plain 76cc iron heads & a small cam.
Production 1971 L48 270 fwhp w/ dish, plain 76cc iron heads & VERY small cam.
Last edited by jackson; Dec 31, 2007 at 11:19 AM.
Racer
Joined: Dec 2009
Posts: 380
Likes: 0
From: Glendale AZ
There's an article from a few years back one of the Chevy magazines making 336hp on a Goodwrench 350 with performer intake/hot cam/ headers and a mild porting job
And those do use 882-style heads and 8:1 compression.
http://www.corvettefaq.com/c3/goodwrench/gm3502.htm
And those do use 882-style heads and 8:1 compression.
http://www.corvettefaq.com/c3/goodwrench/gm3502.htm
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Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
http://forums.corvetteforum.com/c3-t...ads-again.html
This has already been gone over. I said the same thing post number 18, if you keep everything the same and swap heads the higher compression nets some power and the advantage of timing nets some power, but flow up to about .400 is really negligible. One head I have found interesting in the flow chart is the Blackstone ported WP s/r torquer head. Nice read about the buildup of the crate engine too, would have been nice to see the vortecs first without porting though (actualy they did, sorry). I would think a good valve job and bowl blend would get similar results from the 882 heads.
This has already been gone over. I said the same thing post number 18, if you keep everything the same and swap heads the higher compression nets some power and the advantage of timing nets some power, but flow up to about .400 is really negligible. One head I have found interesting in the flow chart is the Blackstone ported WP s/r torquer head. Nice read about the buildup of the crate engine too, would have been nice to see the vortecs first without porting though (actualy they did, sorry). I would think a good valve job and bowl blend would get similar results from the 882 heads.
Last edited by tt 383; Jan 8, 2010 at 08:14 AM.
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
Kind of interesting but this page has flow data for several heads....
http://users.erols.com/srweiss/tablehdc.htm
and all I can see is that 882's are really not that bad of a head.
It seems that the flow results (and desktop dyno results from them)
don't make that large of a difference....
Just my opinion...
flat tops and a cam get you near 290 hp...
is it the torq I'm over looking?
thanks
tim
http://users.erols.com/srweiss/tablehdc.htm
and all I can see is that 882's are really not that bad of a head.
It seems that the flow results (and desktop dyno results from them)
don't make that large of a difference....
Just my opinion...
flat tops and a cam get you near 290 hp...
is it the torq I'm over looking?
thanks
tim
Interesting results for sure. Yea 882's are not that bad for a street engine. Even combustion chambers look good on a 882. But some and this always gets me say that small chambers flow better! The size bore it flows into will mean more. Not many look at a whole picture. Meaning that air flow will be different on an engine because of the different bore sizes. Ok you flow two heads on a 4" inch bore and say this one is better, maybe, on that 4" it maybe but also soon as you put them on a 4.125 bore you could and usally do see that change, the other set of heads may flow better now. See a flow bench will flow air at a given presure and bore size. An engine really changes the low presure in the cylinder throughout the rpm range, remember it is the piston down stroke that lowers the presure in the cylinder and atmospheric presure is what fills the void. Anyway I may not of made this sound too clear but you really do not need much of a high flowing head on the street and 882's will be fine in most areas and the big chamber unshrouds the valves just fine. Now your valve train is another quistion such as press in studs, no guide plates and other things!
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Open chamber heads flow more than closed chamber heads.
I was surprised to learn than the open chamber heads flow more than the closed chamber heads of the same vintage - even after pocket porting.
But more power is made in the tighter chamber with the small chamber heads even with less flow.
Has to do with velocity and flow pattern but even for the same compression ratio the tighter chamber head with lower flow numbers will make more power.
Gets too technical from here so take it or leave it.
cardo0
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
I was surprised to learn than the open chamber heads flow more than the closed chamber heads of the same vintage - even after pocket porting. But more power is made in the tighter chamber with the small chamber heads even with less flow. Has to do with velocity and flow pattern but even for the same compression ratio the tighter chamber head with lower flow numbers will make more power.Gets too technical from here so take it or leave it.
cardo0
I thought higher flow numbers with the same compression will always have the capacity to make more peak HP. I also thought that an open chamber design will unshroud the valves more and fill the cylinder more efficently increasing VE and peak cylinder pressure making more power. Seems I have been mistaken.
Your technical knowledge continues to amaze me.:thumbs
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
It's been a short happy new year.
I didn't want to elaborate on this because i don't fully understand it myself and would probably screw it up trying.:o But for those also in disbelieve D. Vizard explains it in the first few chapters of "How to ... Cylinder Heads". Yes it was difficult for me also to believe it but he made it a direct comparison and acknowledged the open chamber head flowed better both stock and pocket ported. But that head would still make less power than tight chamber heads at same c.r.. No i didn't prove this on a dyno but i believe D. Vizard has. U would have to read it for yourself.
I really don't care what anyone believes here i just wanted to share something that could be very helpful information in $$$/hp - even to those on my ignore list.
No flames folks, u just have to read it for yourself. Or else spend the $$$ for the dyno time to disprove it and please share it with us.
BTW FWIW u can take a look in the GMPP catalog for sb cylinder heads and you'll see the higher performance heads have the tightest possible chambers.
cardo0
I really don't care what anyone believes here i just wanted to share something that could be very helpful information in $$$/hp - even to those on my ignore list.
No flames folks, u just have to read it for yourself. Or else spend the $$$ for the dyno time to disprove it and please share it with us.BTW FWIW u can take a look in the GMPP catalog for sb cylinder heads and you'll see the higher performance heads have the tightest possible chambers.
cardo0
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
The earlier Vortecs were the best ones 906 and 062 non Mexican castings as the later ones (MEXICAN CASTINGS) the intake runners have an appox. 159 CC runner not a 170 as advertised, I have questioned GM about this at the PRI SHOW for the last 3 years and they say they will look into it but never haved.
There is such a thing a quanity of flow and such a thing as quality of flow and the good Vortecs fall in the quality of flow.
We build a lot of circle track engines and we have seen on the dyno that the Vortecs over the 461 and 462 heads 11:01 two barrel engines 450 lift rule we have on average a 25 horse gain over the older camel humps.
The Vortecs have a raised intake and exhaust runners fast burn chamber which are a big aid in horse power.
A few years ago we built a street engine for a 79 Grand Prix and it was a 355 with light weight parts and Vortec heads and hyd. on the dyno it made 432 horse and 460ish on the torque and in that heavy car its a kick a$$ engine.
There is such a thing a quanity of flow and such a thing as quality of flow and the good Vortecs fall in the quality of flow.
We build a lot of circle track engines and we have seen on the dyno that the Vortecs over the 461 and 462 heads 11:01 two barrel engines 450 lift rule we have on average a 25 horse gain over the older camel humps.
The Vortecs have a raised intake and exhaust runners fast burn chamber which are a big aid in horse power.
A few years ago we built a street engine for a 79 Grand Prix and it was a 355 with light weight parts and Vortec heads and hyd. on the dyno it made 432 horse and 460ish on the torque and in that heavy car its a kick a$$ engine.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
I think you might be refering to the fact that closed chamber heads have a fast flame travel front. A modern open chamber, fastburn design with flat tops and tight quench will outperform a closed chamber head with a dish piston that is the same compression. Your taking a quote out of context.
I thought higher flow numbers with the same compression will always have the capacity to make more peak HP. I also thought that an open chamber design will unshroud the valves more and fill the cylinder more efficently increasing VE and peak cylinder pressure making more power.
Parallel two-valve combustion chambers, typical of American V-8s, suffer from a problem called valve shrouding (Figure 3). This is more common on OE heads than aftermarket heads. On production closed-chamber SB Chevy heads where valve shrouding is prominent, be aware that if larger valves are installed shrouding will get worse, as will flow. The installation of larger valves must be accompanied by a like amount of valve de-shrouding.
http://www.popularhotrodding.com/eng...ads/index.html
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Yes i could do better.
pewter99, i have to say there is someone who shows up to a thread with nothing but a slur like "Your technical knowledge continues to amaze me." is very difficult to deal with. And it goes from one thread to another and from one year to the next. I want nothing to do with this personality that's on the top of my ignore list but he continues to quote, misquote and slur me from thread to thread.
I would enjoy just participating in one post without getting quoted, misquoted and slurred by you know who. Let me know what i can do to post here without a determined stalker to deal with.
Thank you,
cardo0
pewter99, i have to say there is someone who shows up to a thread with nothing but a slur like "Your technical knowledge continues to amaze me." is very difficult to deal with. And it goes from one thread to another and from one year to the next. I want nothing to do with this personality that's on the top of my ignore list but he continues to quote, misquote and slur me from thread to thread.
I would enjoy just participating in one post without getting quoted, misquoted and slurred by you know who. Let me know what i can do to post here without a determined stalker to deal with.
Thank you,
cardo0
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
There are a ton of factors beyond just the "open-ness" of the chamber. Heck, the D-shaped chambers on "smog" heads are VERY "open"...and the chamber shape alone will dump 25HP or more (per Vizard). Take an AFR or Trick Flow head and look at the shape for a bit - it's facinating and clearly requires a level of engineering skill and testing that can only be wondered at.
The Vortecs have the benefit of a ton of work by GM - keep in mind that better combustion = less emissions + better fuel economy; so we just get lucky that they make the iron Vortecs available so cheap. It's really the best entry-level iron head out there for the money.
Engine discussions are always kinda...spirited, as there's a lot of different experience and expertise out there. Broad generalizations are almost always going to hit a rock, as there are just too many factors to consider without getting into a specific build for a specific purpose.
The Vortecs have the benefit of a ton of work by GM - keep in mind that better combustion = less emissions + better fuel economy; so we just get lucky that they make the iron Vortecs available so cheap. It's really the best entry-level iron head out there for the money.
Engine discussions are always kinda...spirited, as there's a lot of different experience and expertise out there. Broad generalizations are almost always going to hit a rock, as there are just too many factors to consider without getting into a specific build for a specific purpose.