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I am building a 355 CI SBC engine. I am looking to add a pair of Budget Cast iron high performance heads. Which type would be better for high performance street use:

Dart Iron Eagle II 200cc Intake Runner
64cc Combustion chamber
2.02 Intake & 1.60 exhaust Valves

OR

GM Vortech Heads with 170cc Intake Runner
64cc Combustion Chamber
1.94 I & 1.50 E Valves

Thanks for the assistance !

Joe
 

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hey joe!you havent said what cam you are thinking about using,what kind of engine you are wanting to build[street /strip/inbetween?]anyway,the vortec heads are touted by tons of knowledgeable folks for good reason,they produce!WHAT THEY PRODUCE IS LOTS OF USUABLE TORQUE.,DOWNlow.and the price is almost impossible to beat[try scoggins-dickey ]by the way joe,how many engines are you building currently?,just trying to keep track!see ya!jimm
 

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Do remember, that the GM heads flow quite well out of the box, but ther is NO option for porting, unlike the Iron eagles...
 

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They come flowing very well, as good as the iron eagles do out of the box, but they cant be ported any more... The Iron Eagles can.
 

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Joe: there has been a lot written about the L31 Vortec heads. Scoggins Dickey has a chat board and you can do a search there for comments about the heads, but I can summarize it for you here.

They will flow well to 4500 rpm and then begin to fall off, so they will not make a race head at all. They flow better than any stock head GM has ever made for a SBC, better than double hump. However, they do not respond positively to porting. You can port them, but you will end up with negative results. They are already optimized. Even adding bigger valves yields little return. But you can build a 425hp motor with them right out of the box.

Though they are inexpensive to buy, there are other considerations. You must use an intake dedicated to them because they have a different bolt pattern than the older style heads. They have no guide plates and are designed to run with self aligning rocker arms. The maximum un-modified lift is .480 so the biggest cam you can get in there is the XE268H from CompCams which has a .480 lift (this is a stout cam however). You can mill down the spring seat and get more lift but frankly I would question the wisdom of doing this because the return you would get would be limited to below 4500 rpm. You cannot use 1.6:1 rockers because this would yield .528 lift. on a .480 cam. You also must use stiffer valve springs because these heads were built with mileage and a mild cam in mind.

So if you want more power than these heads will produce as stock, you better look elswhere. If you want a really nice street motor for a low price tag, you can't beat them for perfomance v. $. If you want 600hp buy AFR.
 

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I would think that the Dart heads were more flexible then the L31's. No need for the dedicated intake and plenty of porting for future upgrades to any engine.

[ August 20, 2002: Message edited by: chevelle6869 ]</p>
 

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F-1, your vortec comments really rock! what about the gm non-vortec bow-tie variety? :D

[ August 21, 2002: Message edited by: bullheimer ]</p>
 

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Go to this site for GM parts, then you can say GM does make real good heads, this site gives all the info on engine parts,crate motors 377,383,502 motors with a warrenty. LOL George
They have heads,cams,intakes,spayed valve heads anything to do with racing.

www.spoperformanceparts.com

[ August 21, 2002: Message edited by: 1BAD80 ]</p>
 

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Just for some numbers go to www.chevyhiperformance.com look to the left under Car Tech then look at Tech Articales then go to the right collum click on The best Of CHP Tech scroll down click on Engine. This should open up aouther screen click on Giant Cylinder-Heds...... if you go to the bottom of this page you will see several different categorys for heads.

[ August 22, 2002: Message edited by: cc69 ]</p>
 

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I know this is an older post but I had to reply :)

Who said you can't port vortec heads???

David Vizard book "How to build Max Performance Chevy Small Blocks on a budjet!" goes into detail with graphs on how to do it! Updated 1999 Also shows how to port all the other heads as well and what you can expect: Vortec, 186/041, Corvette, World, Sportman II, etc.

Out of all the books on the subject this is the best one in my book...plus it has a long of other very good info!

True just adding bigger valves won't do it unless you do all the other work that goes with it!

Ported vortec heads with 2.05/1.6 valves:
at 28" on Quadrant Scientific FL 520

Intake:
.100 70 cfm...
.200 140 cfm
.300 200 cfm ...
.400 238 cfm ...
.500 250 cfm max to .700 lift.

Exhaust:
.100 69 cfm
.200 125 cfm
.300 160 cfm
.400 185 cfm
.500 195 cfm
.600 205 cfm max to .700 lift

Stock Vortec head flow numbers: 1.94/1.5


Another good link to compare aftermarket heads to:
<a href="http://www.kendrick-auto.com/head_flow_figures.htm" target="_blank">http://www.kendrick-auto.com/head_flow_figures.htm</a>

I don't know about you guys but these are pretty good numbers esp on the exhaust side! He also brought out that there was not much additional flow just by installing bigger valves or pocket porting them as you need to unshroud the bigger valves along with some additonal work to the guides ect....without this they flowed the same as the stock valves...wish he would of showed pocket porting just on the stock valves though :(

Best pricing I found on this book was on <a href="http://www.amazon.com" target="_blank">www.amazon.com</a> ISBN book number is: 1-884089-34-8

Any other good updated porting books out there guys?

Ken

P.S. Here is an inexpensive elec head porting tool...I use the craftsman from Sears but this one is just if not better :)

<a href="http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44141" target="_blank">http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=44141</a>

[ May 17, 2003: Message edited by: Ken-96GMC K1500 SC ]</p>
 

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read lots and even posted a few on the virtues of the vortec heads, but am looking for something that can handle more. i am pretty impressed with the latest gmpp ad with the big gold head. at the bottom are the "Fast Burn aluminum head". they come from chebby complete for $1100. that guy who's the nat'l champ in whatever class says he runs them unported right out of the box. uhm, found it:490HP from 355cid, stock lift cam and stamped steel rocker arms. p/n is 12464298. the $1100 price is from jet chevy in everett, which isnt exactly the cheapest place around, either. i would like to have 510 lift. (which isnt stock) so i have to see if i have to do anything to them. i would like to know what kind of cam this "worlds fastest stock small block" is running. maybe mike adams has a website and doesnt mind telling all his competitors what's in his engine-haha
 

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I have a friend running a 72 nova with vortec heads with the stock valves. Best time is 11.05 in quarter with 1.94 intake valves. There is plenty of power to be made if the engine and drivetrain are well matched and built right. The key is matching everything. But that's just my opinion, I could be wrong.
 

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Head Bolts

Ya know....I've got Iron Eagles on my 383 that I built.......and one of the head bolts broke after a number of years (#16)......and #2 on the other side stripped.

I was looking at how thick those heads were, and comparing the stock head bolts to that........and it is CLOSE. I mean they are BARELY long enough to grab.....so I'm thinking.....are there longer/special head bolts for the bottom row of the Iron Eagles?????

PS. All this bull**** about a post being too old is just that.....BS.....Google was kind enough to lead me here, so that's good enough for me........A lot of us are working on older vehicles......and besides....Information NEVER GROWS OLD.........fwiwz
 
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