Chevrolet Cylinder Head Dyno Test 

This content right here is EXACTLY what I like to watch.

Back in 1993, when i was in my early twenties, i took the same pair of GM 882 heads, had them ported, polished, went with stainless steel valves, kept the 1.94 for the intake, but went 1.60 on the exhaust, screw in studs, bolted to a freshly rebuilt 4bolt mains 350cid bored .030 over, with four valve relief flatop hyperutectic pistons, stock 5.7 rods, single pattern comp cams hydraulic 270(224@.050/110ls/.470 int&exh), comp cams 1.52 roller tip rockers, ARP bolts throughout the entire engine, eldelbrock rpm dual plane intake, holley 3310 750cfm vacuum secondary carburator, msd6a/hei ignition, 1 5/8'' headman headers, 2 1/2'' dual exhaust, flowmaster dual chamber mufflers with tailpipes to rear bumper, rebuilt stock th350 with b&m shift kit for firmer shifts, b&m 2000rpm stall 12'' torque converter and a 4:10 10bolt positrac rearend, neadless to say, this combo might not have been ideal and a total waste of money when it came to the modified work on the heads, given the better alternatives at the time, but it netted me consistant 14.40s in the 1/4mile in a 1975 chevelle 2dr, all engine... it was my very first street/strip car, so it was a learning process, and it didnt dissapoint.

I just picked up my original 896 PowerPak heads from the machine shop. 896 heads are a 59cc chamber stock. They installed 2.02 intakes and 1.60 exhaust Manley stainless swirl valves, max flowed each, installed new guides, and they look GREAT! Flow on the intake side is at about 205cfm and the exhaust side is about 138cfm at .500 lift. He spent the most time on these heads for me and the total charge for parts and labor was only $550.00!! Over 1500.00 bucks is a very high price.

This is true, I bought a set of 062 vortec heads, and after doing all the work my self and buying all the tools I bought to work the heads I ended up spending more than buying some nice brodix heads ( not to mention the headaches). The best part of doing the work myself was learning how to do it.

AFR all the way. Made 552 hp on a 383 with the 195cc heads with a port matched AFR intake and roller cam.

I saw a NHRA "Stock" 1974 350 make 437hp at 6500rpm on a dyno with "stock" 882 heads and stock intake & Q-jet. Must be magic.

Installed several sets of these, they come set up w/correct accy. Patterns + accepts int. & ext. Bolt valve covers. Saves $$$ & time.

You are right. As long as you are happy with what you've got, that's all that matters. Hope your engine runs like a champ!

Stock worked heads produced: Bottom tq 385@ 3500rpm Peak tq 397@4500rpm 375 tq & hp crossover @5200rpm Peak hp 383 @ 5300rpm... After dart iron eagles: Bottom tq 420 @3500rpm Peak tq 445 @4500rpm 425 tq & hp crossover @5200rpm Peak hp 446 @6100rpm...---- big clues up too with 370 tq vs 445 tq at 6200rpm where better heads maintain power (maintain torque at high rate of revolutions) and stockiest drop off steep after that 6200-6300.

Should have compared the vortec heads instead of the 882's. Vortec heads are the only stock heads worth using on a gen 1 small block, vastly superior even to the famous "double humps."

only problem here is a stock set of chevy vortes heads flow around 230 to 240 cfm ... those would have shown a real comparison!

Can't imagine ever using iron heads these days. The flow rates very retro. Really shows how good the new stuff. Even OEM 4vs now that are flowing 250+ cfm stock.

That's exactly that point. With the 882 heads we cut the decks until we started cutting the intake valve seat. You can get the chamber any smaller without angle milling the heads, then you get into all kinds of extra costs and issues like the valve angle no longer matching the valve pocket in the pistons. Likewise, putting larger valves in the heads is pointless unless you do some grinding in the ports, and that costs a lot too. Now you are talking about putting crazy money into stock parts.

Thanks for doing this so I don't have to find out. This is an amazing format for a video because it really busts the myths. It's also very relatable to a common enthusiast.

$1250 for Dart Iron Eagles? Why not just buy some AFR 195s or 185s for $1500 and you will get aluminum cnc machined heads that annihilate the Dart Heads' flow numbers and maintain port velocity.

Those are the best head's I've ever seen!Dart definitely figured out the head's!

I love tests like this. How about comparing all the popular after market heads?

Back in the early 70's I was building a sleeper so I sent a set of power pack heads, as they were known then, to AFR. They were able to spec them out slightly superior to the fuelie head numbers. I also had the good fortune to be working in an automotive machine shop at the time. I came across a 350 "X" block that I was able to bore and stroke to 388 CID. Used all the then popular parts, Jahn's pistons, Crower camshaft, Mallory ignition etc... I was able to make a 1963 Chevy II into a raging monster pushing that little shoe box into the low 10's. I realize today that low 10's are anemic but back then it was highly impressive as Pro Stock cars were only in the low 9's. Never put it on the dyno but I'm guessing it was making a skosh over 550 HP. Just pointing out that it is possible to use these heads and make good power but today it is not economically feasible. Back then you used what you had or could find at a reasonable price. If you wanted to put a blower on your car, for instance, there weren't any "kits" you could buy so you had to search the wrecking yards for a 471 or 671 blower of a diesel truck and machine it to make it fit a small block. With the technology today it is easier to make big power but it's still expensive. Gotta say though, as a G-force junkie, more fun than should be allowed. Peace out and happy racing.

This is just what ive been looking for. I have an old C10 with a 350 and its just a cruiser, i dont want to put a converter and gears in it and spin the motor to 6000 rpm. I just want to maximize the power from idle to 3500 rpm where the engine spends all its time and i figured cylinder heads weren't really gonna do anything for me in that range. This confirmed that suspicion! Ill just toss some headers and a small cam in it and call it a day.

At 5:30 into the video, the flow bench clearly shows the stock head intake flow curve lay down flat at .400 lift, not even close to the .500 comparison point. I'm sure Dorton knew when he put the 1.94 valves in there that the chamber needed unshrouding, or it would possibly even HURT flow. 1.84s might have done better. But that's probably not even as bad as leaving the exhaust valves stock 1.5 (which made sure they'd look very lame next to the darts.) Still, it's a tribute to old-school Chevrolet manufacturing that these castings could even stand in the same test with a set of 2013 aftermarket castings. Money/time are also confounding and distracting variables in this kind of experiment. Obviously most of your viewers would never dump $1500 into a $50 set of stockers. They'll have something better lying around (like Vortecs) in better shape. So unless you're actively working for Dart, you'd be much more objective just revealing the $$ info at the end, for those interested. That said, thanks very much for the presentation--very clear and informative.

5:05 - thats a heck of a nice ridge/step left in the throats of the Dart iron eagle heads! Intake and exhaust need some time with a stone burr

That's remarkable because when Dart first introduced the Iron Eagle series heads many years ago, they advertised a 75hp advantage over stock heads

I have iron eagle 215s on my 350. They're damn good heads. They put me over 600hp NA and pull strong well past 8000 rpms

Fantastic video. I have several sets of 882 heads. Some have either 1.94 or 1.72 intake valves and have gone some porting work on both. Everyone I have ever talked to that has said that they are only good as boat anchors and I am wasting my money on anything I do to them. I can definitely see what they are talking about with this video.

im learning just how much power can be gained from better heads CFM

Interesting- does anyone remember the small block Chevy 'angle plug' heads from the late 60's or early 70's? I think they were a Chevy performance over the counter head? Supposed to be for higher compression engines back in the day

Great video. I used to do that type of machine work on heads because years ago off the shelf cylinder heads did not exist at all so that’s what we did. These off the shelf dart heads you can’t beat them, and the hours porting and polishing what a mess

Since everyone gets gm vortecs, get a stock pair clean them and add stainless vavles to some of those! Then compair. Since you can get vortecs between $35 (pick-a-part tuesday special) and $250 any were else.

Also forgot to mention that the compression wasn't the same for the shaved 882's vs the aluminum heads an even smaller chamber but for something thrown together for 380 +hp and 390 lb-ft

It's a good test for newbies to the SBC. Back in the '90s I remember learning just how much stock Chevy heads suck. Aftermarket heads are the only way to go once you're set on rebuilding a 350 for reliability or performance. Thanks for the video.

Bought a very clean set of 823 castings l98 heads with rockers for $650,,,, and sold my used Dart Iron Eagles 215 /64cc for a $1000. No more first generation Sbc for me as I go forward,,,,, just LS swap it,,, lol

The driving torque is unreal; will try a set of the Dart heads on the next build.

im doin a 67 327 w/ stock valves lil porting on the exgaust nothing fancy. ls6 springs comp retainers holley 650 dp summit stg 3 intake 1" spacer hooker. headers. lt 1.5 comp rocker tips

Solid cam 248/252 (advertised) with about half inch lift, solid flat tappet, 350 ci sbc, scat moly slugs (don't know if flat top) scat crank. 1&¾ headers from Dyno setup.

my 1978 z-28 Camara had a smog whopping 165 hp.

You could have milled them down to 62 or 64cc I've done it make it fair . 193 at 500 lift at 28in .,I don't think that's right. Chevy has made plenty other heads you could have compared them to.

It is always interesting to see, that torque scales LINEARLY with the flow cfm of the cylinder head (regarding same intake runner size in cc, which is important, because otherwise you once again play around with the rev band, like with camshafts, too). So comparing modern heads, which can flow up to 250 cfm, porting them slightly, which can obtain up to 280~300 cfm if you know what you do, you will just gain DOUBLE the power comparing to a stock 70s chevy iron head, which does about 150cfm. You can gain easily 300 horsepower instead of 170, with a stock cam. With a smooth idle, with a good gas mileage, with just pulling the heads and replacing them, which can easily be done in-car without a full engine overhaul. (Just remind: You might f*** your bearings and piston rings then ..... hahaha)

Ken this test was done with flat tops from the video.... you can run 64cc heads and flat tops... most dart ie 64cc heads measure out to really be 65-68cc...mine measured at 65.5 and the 5cc speed pro pistons actually measured 6cc reliefs....with a larger duration cam to bleed of some of the compression at lower rpms and lower the dcr it will run great. Especially with the newer chamber design.

sbc 441 heads are a good choice for a budget street head .

I had that same 882 head on sbc small block and it lasted over a year running hard I had.510 lift camshaft and. Around 300 or so up never broke anything in valve train. That cylinderhead you just shown dart should be better next engine I do im going to look at those heads thanks for showing those other heads.

I look for Torque below 5000 rpm but starting at 1000 rpm ! No racing just street throttle response !

I don't think your comparison was fair because you started out with boat anchors from Chevrolet. A pair of Vortec heads would have been more in line.

Excellent comparison. I just watched it again today. I appreciate all of the good work you put into sharing it with us.

Are they faster if you paint them chevy orange ?

It might help if you included the cam specs and cubic inches for this engine.

I run the alum pro1 230 on my 427sbc good heads. if you go stock you will have to machine them

This is the kind of advert that I don't mind at all!

I love the test, I would just say if you are going stick with the SBC, go for the aluminum versions, they save close 50lbs. That will yield a slight improvement in handling plus that much less mass for your car. One problem is though for the cost of those heads you could pick up a used LS2 for about the same amount. That's going to make more power throughout the rev range, less likely to leak oil, and weighs over 150lbs less. Sure it's not as easy on the eyes I get that but the smiles from inside the car will be greater.

i just give a set of 194 camel hump heads away for free but i just got 2 454 strokers one with only 6000 miles on it the other one has 38000 on it both with the heavy duty 400 turbo that is the cheap stuff i got for free so far this year i just love the 4x4 short box pu 79 chevy with under 36,000 miles on it factory paint is still in mint condition

Those Dart Iron eagles are more expensive that Brand New Vortec heads.

To get a big boost in hp you need to up the compression to over 10-1, or 11-1..you can't get hp with 8-1 or 8.5. I can remember in the 60's they were running 13-1.

I have a pair of these Dart heads sitting on top of a .030-over 350. They do pretty well for the $900 I paid for them. But for $1200+, I'd go for Trick Flow or even Dart's aluminum heads.

I would like to know the best aluminum heads for a sbc 383. Have world products cast heads now. Running flat top pistons. Flat tappet cam comp xe284h

they could have put some thicker head gaskets on the Dart to make the compression equal. Not that it matters, they should have used Vortec as many have noted and probably a better aftermarket head as well.

to remove studs i put a small pice of pipe or tube over stud and tighten a old rocker nut with a washer

Hey Derrick. Loved the episode on rebuilding the 307. Just a couple of questions. Did you use new cam bearings on the block or leave the originals in there. Also, the new bearings you used for the main bearings and rod bearings, were they 10 thousands under or stock size? Also, were the rings the same size as stock or 10 thousands over? Love all your episodes. Keep them coming.

Thank you for doing all the work so we could learn.. !

I don't understand how this channel only has 8,000 subs

I wonder how the Edelbrock Performer RPM heads would compare against the Iron Eagles?

But the real question is? Can Dorton make those Iron Eagle heads even better than straight outta the box? If so,how much is the MAX #&$?

I always heard it pronounced “two-oh-two” not “two inches twenty thousandths”

Also I heard the cam numbers but what cam? Hydraulic roller, hydraulic flat tappet? Solid flat tappet?

How about using a set of L98 Corvette aluminum heads? I'd be curious as to how those would compare to the aftermarket aluminums. Since you can get those for around $350-$400 off of Ebay.

A more true comparison would be Dart head against a Vortec 062 with the fast burn chamber because the Dart head has the fast burn chamber and that makes the head really flow well. They try to sell Dart heads by throwing off on stock heads but they don't tell you that a Vortec head can make as much as 480 hp and costs around $350.00 per pair used and in good shape.

I agree that they chose the wrong heads to compete with, they should have used the 041x,492 ,186,291 just like what the other guy texted that this is a dart advertisement to sell their head if you really search you can find the castings I posted check out Craigslist,yard sales, machines shops,and just asking​ and looking around but if you have the money for an after market head then bye it.its also all about what do you want to do with your motor and what kind of power your looking for

That's like an advertisement for DART, what head do you think they would have chosen to compare against? Let's see...if you were going to show off in a foot race would you choose to compete against the fat kid or the athletic guy? Maybe try comparing the iron eagles against a head that someone would actually pay to have re-built. 882s...LOL

What about a milder engine with dual plane, mild to mid street hydraulic with .460 or .480 lift, smaller tube headers with the stockers against a smaller port Eagle. I am thinking about a "torqueyer" street engine (350) which uses the better velocity of the stock heads rather than just the flow.

To bad I have a set of 186 69 Camaro hump heads I just been redone with port polish and springs good to just over 600 lift I would have loaned them just to see what they could do.

you can get much closers numbers from the stock head if they had bought the darts at 68-70cc. lowered compression on big displacement is a huge loss all over the map on top of longer cnc machined runners.

I wander what the Chevy heads would produce with a fully ported job would have result because we all know the dart runners are casted that size to start with I don't think this is a fair comparison port the ,882 heads and Dyno again I am just curious how much power a stock set of heads will produce

One should never bolt on a set of ANY aftermarket cylinder head. I always completely disassemble aftermarket heads and check >>EVERYTHING>> . Spring height, seat runout , seat and lift pressure. There is errors 99.999999 % of the time. They are massed produced so the will have errors everytimel, guaranteed. The biggest issue with my experience is the guides and the eat runout which I alway correct.

should have tested against vortec.. would be much better comparison as combustion chambers are similar modern design and would have been same compression

I'm going with the dart!

Thanks for the video it answers a lot of questions.

Compare those Dart Iron Eagles to a set of Summit Racing Vortecs @ only $317 each. Think I would go with the Vortecs.

Talk about comparing Apple's and oranges this is a no brainer. Smaller chambers, better runners, bigger valves=much better performance. Compare these to double humps or vortecs. Still should out perform, depending on cam, etc.

I'll take AFR heads over Dart even if they cost twice as much....

Just come out and say I am a salesman for Dart.

epic. 6:50 modified GM 882 heads. 8:20 DART iron eagle heads.

i love seeing smog head runs where soooo many people on forums claim oh even reworked 882 or 993 heads you'll be lucky if can top 300hp, i have a set of 993 i bought 15+ years ago from Arrowhead with studs, undercut stem s/s 2.02/1.60 valves with .525" lift springs ,optional bowl port that looked nice they know what therr doing where there are a sub division of indy cyclinder head and i did a bunch of pocket and guide boss work & runner cleaning up and exhaust polishing and they make my 355 run pretty strong i 2wd chevy truck, and they still sell the same head fairly cheap. the thing i wonderd is why would you put allll that work in cracked heads then toss em?? sees foolish not just go get a decent set of smogers...? then somebody could used em on a mild sbc, you can usally find em for free especially old wore out ones with all the vortecs out there. i bought a set of vortecs for $60. regardless cool video!

Who rebuilds 882 smog heads.

882 heads make good boat anchors. Dart makes a decent head but how to they compare to the Vortec Head? A few hundred more will get you into AFR Heads which are in a different league. (Next to the Darts)

Not sure just how much porting he did but I have had 882s run much better then that with 1.94 with a spec Cam and spec compression for a street stocks class at a local race track I got over 450 hp so not sure what you guys did but I spent 600 on my head's and did the porting myself

Everybody looks for a set of double humps but 041 and 041x are much better due to having accessory bolt holes on the ends of the heads and the exact same performance as a double hump....plus it's been my experience that half the time you find a pair the person selling them doesn't even know what they have....in the past I'd scored multiple pairs for 150 bucks. I'm all about LS Motors now but if there where no such thing as LS I'd building big solid roller destroke 377's or long rod 408ci with Pontiac 18 degree or sb2 heads.

People need to watch that video twice before commenting it seems...heads were milled to 69cc and along with all the other work done they are still poorly designed chambers and horrible ports. Double Hump heads are only good for the resto Corvette engines. Vortec heads are the best OEM bang for the buck in stock or ported form..I would even put them up against the Dart heads used in this test.

So even a 1970 350/300 10.25:1 compression head isn't worth doing anything with, I would still have to do most all the same things as the 882 head? I do figure them to be 1.94/1.60, since they are the 300hp heads...

That's cool, though. Even if it did cost more money, there's nothing like the feeling of knowing you did it yourself.

Was it an illusion the crossover looked a different RPM on eagle heads. It might be the camera giving the wrong impression.

Cam and short block specs please!

Why not get some 041/186 heads? They’d probably be a better stock head choice imho

great video but I got my iron eagles 200cc for 795$ brand new 202 160 price shopping and they are awesome

double hump heads 2.02 valves have more flow & give more compression ? witch = more HORSEPOWER

I pair of 202's against some large chamber lower compression 194's Really Really what a comparison

As a Bakersfield native, I need to know what shirt he was wearing during the engine dyno!

Great test!!!

Maybe the test would be different if they used 062 casting Vortec heads,,,, I find them at my local pick-a-part for $50.00,,(castings 906-truck,,062,car,,although I've seen them on trucks-suv,s)

But you didn't run a vortex head why

Ok good video and what does the stock L31 vortec heads stack up against the Dart Iron Eagle,,, vortec heads are cheap new,, can we see a comparison. Dart heads are a hot rod head designed to make power,, the stock chevy vortec heads were simply a production thing that hot rodders picked up on,, I have an old 400 +060 with vortecs curiouse to see

Could t get a pair of Vortecs?

Do you think they make a set for a 4.8 liter Chevy and if so is it basically just a plug-in play??? out with the old in with the new???