Later this summer I am going to finally get rid of the Dart 2 heads and move up to a set of aluminum heads, but I'm looking for opinions on which head 1st.

Here is what I'm looking for out of a new set of Aluminum heads:

1) 54-58 cc chamber after porting. (With my 14cc dished pistons I need a small chamber to move the compression up to 10.5)(Darts are 64cc currently)

2) I would like to achieve 290 cfm by .550 lift, yet still keep the intake runner size @ 210 cc or smaller... ideally I would love to keep this more in the neighborhood of 200cc considering this is going on top of my Superram equiped 383. Actually, I would love to see 300 cfm @ .550 lift with 200cc runner. Is this possible ? Which head ?

btw, I have read everything from 5 hp to 25 hp gains on a boost in compression ration from 9.8-1 to 10.8-1.... does anybody have a practical educated guess on HP increases with a point jump of cr ?

Also, what about additional head air flow ? My Darts currently flow approxmiately 260 cfm @ .550 and 190 cfm on the exhaust. I am hoping that there is some sort of HP gain worth mentioning with new aluminum heads that flow in the 290intake/210exh area.

As a note, while apart, the SR plenum, runners and manifold are going to receive a thorough porting job.

thanks
Beach Bum

 

Beach, i'm sort of wrestling with the same issues right now while i have the heads off. i'm trying to figure out if i should open the ports on the heads a little. try to up my flow 10-20cfm. But a) i don't want to open them up too much and loose velocity (particularly on my little old 350) and b) i trying to figure out if there would be any benefit given the air has to flow thru the SR to get to the heads. The best flow numbers i've seen for the SR runners and base were from a ported and extrude honed SR were around 270cfm. Given that, i wonder if there would be any benefit to getting the heads to flow more than 270??? And that assumes my Sr can flow 270 since it is NOT extrude honed.

The other thing you need to be concerned with is the runner dimensions and locations vs the base. If you try to go to the AFR 210s for example, the SR base may not match the normal 210 runner. I'm using the 190s port matched to the ported base and matched to a felpro small race intake gasket; i'm about max'd out. Anything larger and i would NOT get a good seal.

the good news (technically) is that the AFR 190 comp ported heads flow almost 280 (270 @ 550). the bad news is they tack on about $900+ for comp porting :-(

good luck on your quest and let me know what your research turns up.

btw, there is a good head dicussion on one of the threads here or in the C4 section, with some real life examples of high HP applications and opinions on AFR, ARE and GTE?? custom port jobs.

i'm considering getting my heads and intake flow tested, but i'm sort of fighting time as i want to get it back together by friday, otherwise i'm booked until the end of the month.

 

Brodix recently came out with a new head design called the 18x. It features an 18* valve angle, but uses standard 23* valve train. They claim 325cfm out of the box. It also features a spread port exhaust pattern, center water circulation if you want, 40/60 valve spacing, 244cc intake ports, 2.140/1.600 Ferrea stainless valves, and CNC intake and exhaust ports.

I know the intake port volume is larger than you wanted, but I bet they'd make good power, especially since you seem to be mainly focused on drag racing.

To get an honest 300cfm at .550 out of a 23 degree head with stock port locations is a real challange. If you were willing to consdier 220cc+, or a raised port design 23* head, it's pretty feasible.


If you were willing to go up to a 220cc port, you'd have several options. This is just my opinion, based on what I seen on the dyno, but I think the small port trend is a little over-rated. For a 350 that sees alot of street driving, sure you want to keep the port size conservative for throttle response and low rpm torque. But on a larger motor like yours that sees alot of strip time, there's a case for a larger port. Whether you're talking port volume, velocity, etc, what you really want to concern yourself with is port efficiency. How efficiently doe the head fill the cylinder and combustion chamber.

Since everyone likes AFR so much, look at the AFR 220cc Competition ported heads. AFR claims 295 @ .550, 298 @ .600, and 300 @ .650. I has these on my 383 and I like them alot, and never felt my throttle response was lacking, and I know they made good low rpm torque, as I had the dyno numbers to prove it.

AFR also has their 227cc Competition ported heads. They claim 298 @ .550, 302 @ .600, 305 @ .650.

If you were willing to do a little work on the SR manifold to get the ports aligned, a killer head would be the AFR 215cc Raised Runner heads. AFR claims 308 @ .500, 312 @ .550, 315 @ .600, and 320 @ .650. Those number kick A$$ for a 23* head.

Also, Chapman does some really good work with Edlebrock heads that come close to the numbers you're looking at. The one's that really meet your numbers are still high-port heads though, and the ports are 238cc+.

 

Monty about said it all. If you could port match your S/R I would go big cc. 383's have enough TQ for all my around town driving needs. I take it that your not going for a cam change is why your asking about .550 flow? I've seen your great 1/4 times and videos. It will take a significant HP change to gain 1/10's from where your at. Different books make claims hp gains of 3-4 % like in your 9.8 - 10.8 c/r.

 

Monty, were you able to match the SR base to the 220s??? Did you have to modify it? I assume the 220s need at least a med race gasket and i don't think my base would seal with a med race gasket???

 

Monty & Ralph,

I dunno, some of those heads sound awful big... but, I may agree with you on runner size, I think some of this smaller is better hype can be a little overrated. I was told not to go with 200 cc runners on my old 350 Large runner motor, but it ran fine as compared to other similar set-ups with solid short times with a mild 2500 rpm converter.

I really don't mind a small torque loss up to 4000 rpm... probably help me with consistency at the strip anyway. But I'd want the payout to be well worth it above 5000 rpm, thus the question is... Is this additional headflow actually going to add any power ? I think I'd definitely set the window at 220 cc max size. But I dunno, would a 230-240 hurt anything ? Do I have enough motor for this ?

I'm also wondering outloud what rpm can the Superram get to with big heads/219 and a thorough SR port. Currently I am at a 5600 rpm peak with the cam retarded 2 degrees and 200 cc untouched intake runners. I'm thinking anything over 6000 rpm is pretty much impossible with this manifold... and even if it can flow up there, with my 219 hyd roller cam shifting much higher than 6200 rpm, I'd expect float problems.

Ralph, you were telling me a while back about a Cartek 406 vette (Julio's ??) that ran in the 10's on all motor with the SR... did you ever get anymore information on that set-up ? Head information ? Cam ?

btw, does anybody know what the LS-1 heads intake runner size is on a heavily ported set ? I know some of the porters that know what they're doing are getting over 300 cfm out of those by .600 lift, I'm just curious how much they had to open up those runners to do that, or is the efficiency of these new heads that good. I'd like to emulate those heads... too bad they don't bolt on our motors... I'd have em on already.

Ralph, do you know where that head discussion thread is ? I didn't find it at first glance.

btw, I probably will go with Extrude Honing on the stuff... pricey, but it looks like the results are probably worth it.

What to do ??

later
Beach

 

Did you have to modify it? I assume the 220s need at least a med race gasket and i don't think my base would seal with a med race gasket???

Yes, the AFR 220's are port matched to a FelPRo #1206, Medium Race Port. It's 1.31" x 2.21", vs 1.28" x 2.09 for a FP1205 Sotck or Small Race Port gasket.

I opened the ports up to match the gasket and then had to have a little aluminum brazed on the bottom of the port, under the manifold. The machine shop only charged me $60 to weld it. Without reinforcing the bottom of the port the gasket would probably leak, resulting in a vaccum leak in the lifter valley.

I went through 4 different head combinations when I ran the SR. I started with Dart II's, like Beach has now, then went ot the AFR190's, then AFR 210's, and finally AFR 220's before I got rid of the motor in favor of my current one.

 

Gkull,

Thanks

How big do you think I can go on the heads ? Theres gotta be a limit. I'm not against going solid on the cam, but with my Superram manifold, I don't think its necessary considering in any case I'm more than likely bottlenecked with a 6000 rpm or less HP peak with it, which equates to 6400 rpm or sooner shifts. And unless somebody can show me a better hyd roller cam for the SR than the 219... I'm staying with it.

I really want to optimize HP from 4000-6200 rpm, considering my converter flashes to almost 4000 rpm as it is now.

btw, 3-4% sounds well worth it for the increase in cr... that would be somewhere around 12-18 HP.

I think my et's are okay for my mph, but I don't like my mph. I'm running 115 traps in summer air, and 116-117 in slightly better air. I'd like to get it up to 118 in summer air with 120's in good air. That should be good for low 11's if I don't kill my short times. I blame my low cr iron heads, unported SR and 3500 lb raceweight for the 115 traps... I'm going to improve them all this summer/fall.

Beach Bum

 

Beach, i would suggest a new thread asking if anyone has runner 11.2 or faster with a n/a superram. that setup (if any) should give you something to use as an example. If you don't i probably will. right now the only ones that i know about are Julio from car tech and i've heard rumors of 1 or 2 others, but no concrete details. I just don't know if you can get the SR to flow enough at the highend and the TQ becomes a problem getting it to the ground on the short side. Maybe i'm worng, but i just don't see any real life examples around.

 

Monty
Were your afr210 comp ported or out of the box. How would you compare those 2 heads
AFR210 to the 220.

Phil(lt401) is running a full ported superram on his brothers car. He matched it up to felpro 1206 gaskets.
Beach I would lok for great flow numbers down low.
My current AFR do max out a 270 but a 650 lift.
My ported edblebrooks flowed better to 450 lift. Thne the AFr's take over.
Be carful if you plan on sticking wiht the SR.

I see more work involved with combustion,swirl and valves. I have seen different valve job angel gain 5-10 cfm alone.
Compare flow numbers from .300-.550 lift when comparing. Get big numbers with a small post say 200 or 210 you will be better off.
Dennis

 

Dennis,

The 210's were the Race Ready's, while the 220's were the Competition's, so it would be unfair to compare them since the 220's outflowed the 210's at every lift point. Both heads were good heads though, with the right cam, they are hard to beat for the money.

 

Hi Beach, the main issue with keeping smaller runners is velocity. It induces swirl and tumble, which keeps the fuel atomized and induces inertial force of the intake charge. Ideally one would want a large intake opening (velocity stack on a carb) with a decreasing radius pathway to the intake valve.

I fear with the S/R & 219/219 cam, going to a larger intake cc-size will hurt you ET's. You're already doing better ET wise, than most with similar combo's. As a matter of fact I used your engine as a reference for my engine build up!

Although I did buy the TPiS AFR190's, your Iron Dart's probably produce as much, if not more Hp! I think (could be wrong) that your current 260cfm heads can support 480FWHP. Going to Aluminum heads to get a higher C/R on pump gas I think you'll find to be a waste of money. Yes you can run higher C/R with Al. before pre-ignition, but is the cylinder combustion pressure significantly raised-NO! The reason you can run Al. heads with a higher C/R is because they absorb more heat/energy from the combustion event. The DartII/Iron Eagles have modern fast-burn design chambers- just like OE L98/AFR/Brodix /Canfield heads.

Personally I would recommend looking for a local head porting wizard, flat mill off material and find the thinnest head gasket which still gives you 38-45 thou of quench. You should end up with at least 10.25:1, which is as high as you should go with iron heads on 92-Octane!

BTW, although I don't have a formula to back this up, I think if you ask some good Machinists they'll agree: your current 9.5CR iron heads are producing the equivalent Hp as a similar type designed 10.8CR Aluminum head!

Almost forgot, small chamber heads have advantages with low lift cams, emissions, fuel economy. On the other hand, a larger sized chamber provides less shrouding of the valves- I.E. better flow! Believe it or not, modern OEM head design is a small miracle of compromsies!

 

here's the link (at least one of them is)...i can't figure out how to paste the link itself. It's an LT1 discussion so they don't really answer any of your questions directly, but interesting nonetheless.

http://www.corvetteforum.cc/cgi-bin/...3&topic=009755

http://www.corvetteforum.cc/ubb/Foru...ML/009755.html

You can get details on Julio's car at Cartek.net and then click on the red vette doing the wheelie. it was a 406 SR with ported 190s and a big hyd roller with like 13:1 CR and DFI. i think he was running 3.73 gear too. i don't know what the car weighed, but 10.6s are really fast for that setup. i've run it thru the computer and i've got to make all my assumptions aggressive to get near those times. i wish the car was still around, but i think it got wiped out in a flood. Julio used to post here under the name techombre, but i don't see him anymore. i'd really like to pick his brain on that setup.

I've heard of a couple of others but have real sketchy info if you know what i mean.

Ya know Beach, if you are going to rethink your setup, why not sell the SR and get the MR...then the sky's the limit. Plus if you really want MPH, that's the way to go. I'm assuming you want to get to low 11s or high tens with the investment your about to make. I'd want to see some real life examples of SR cars that run that fast (regardless of cubes). Maybe they exist, but i just don't see any. It would be interesting to see what the SR can flow, but there's a lot more to these tuned ports than just flow (as i found out with my runners). the setup has to really work together or forget about it.

I know i'm not telling you anything you don't already know, but that's kinda where my thinking is on this subject.

 

RU4L98,

Thanks for the reply. Your points are well taken. Another reason I want to move to Aluminum is the weight savings.... that 60 lbs is nothing to sneeze at. In addition, while I'm removing 60 lbs from the front of the motor, my train of thought is... "Get the right head that will add some power too "

Another big reason why I want to make the move is the LS-1 motor... An LS-1 with 383 cubes, Ported heads, MTI cam and headers will make roughly 450 rwhp.... where as I with the converter unlocked make 362 rwhp, I assume I would be up around 380 rwhp with the converter locked, therefore, I'm a solid 70 rwhp behind an LS-1.... I ask myself "Why ??" I think its in the Heads, and of course a better breathing LS-1 or LS-6 intake manifold. Those heads really respond to porting and then the manifold allows it to breath to a little over 6000 rpm... but not a lot. I see the peaks at right around 6200 rpm on the stroker LS-1's... and even at 5600 rpm (My Peak), they are making 430 + rwhp. So by logic, even though I don't have the manifold to breath up to the LS-1's capabilities, I should be able to match the LS-1 in power up to my manifolds peak rpm if I too optimize my set-up. The only thing I know about their heads, is that they are considered a modern techncology marvel and that they flow over 300 cfm by .600 lift with competent porting. (This is the reason for my creating of this thread to begin with)

I am sure somebody (Brodix, AFR, Edelbrock) makes a head that meets my criteria and will in theory allow me to make the same HP up to 5600 rpm that a LS-1 does.

I also read this past issue of GMHTP, in which a noted and very experienced engine builder/Teacher Judson Massengill states "Let me tell you there is no such thing as too much cylinder head in terms of airflow, only too much port cross sectional area or not enough motor under the head, if you could have too much cylinder head the justification for Turbo's, blowers and nitrous would take a serious dive."

With those words, I've decided I need more headflow.

btw, I don't think I'm making much HP... in the neighborhood of 430-440 flywheel ponies. And I think others have made more, although not all of them have put it to the ground and produced respectable et's, they have the trap speeds. I gotta believe you made a better choice than I did with your AFR 190's, and I think they easily outflow Dart 2's with equal porting and/or out of the box.

Ralph,

Thanks for the links, I'll check em out in a bit.

Thats a shame that vette was lost in a flood or something... great living example.

You know if I move out of California or I take the Vette completely off the road I'll go Mini-ram/Solid and even more cubes in a heartbeat. But keep in mind the Miniram is Illegal here in California. Cannot run it, no carb #... actually I probably would have made the move to the MR about the time Dennis did if California wasn't so **** on aftermarket products. I have an in at a place right to pass with my illegal headers... but I know he's not happy working their, so he could easily be an out in a second. So I gotta stay with the Superram for now.

But, I do not ever expect to see 10's out of this motor naturally aspirated and at 3500 lbs. But I think 3300-3400 raceweight and a better set of heads and ported Superram and fairly low 11's can be realized. Keep in mind, I've ran a 11.55 @ 117, and forum member 90vette ran a spinning 11.54 @ 118 mph in it at a 3400 lb raceweight, thus its fair to say, right now at 3400 lbs 11.45's @ 118 can be accomplished right now.... I just need to remove a couple hundred pounds and add 20-30 hp and 11.0-11.1's should be doable.... That'd be great !!! But easier said than done as you know.

I know what you're saying about our finnicky motors... I'm thinking about what happened to you every step of the way, but I don't think the standard SR port job and better flowing heads with a 10.5 cr is going to upset the balance of the tuned port... or at least I hope not.

later
Beach Bum

 

Beach i spoke to the machine shop and he couldn't flow the intake until next week at best (barely finished my heads today and is backed up big time), so that's out. i described the intake to him with dimensions and he thought it could outflow my heads...off the top of his head...lol, but would obviously have to flow it.

you are right about the LS1 heads, but they are a completely different design than ours. i think even aftermarket l98 heads would have a hard time keeping up. you usually need a pretty big runner to get 300+ outa a normal runner, 23 deg head.

i guess you're stuck with the superram for now. Net, net, the 60lbs savings will get you 6 hundredths right there. porting the SR has got to help too. as cast, they are pretty rough, plus there is some material that can be removed to give more cross sectional area. mine started out around 1 5/8 diameter at the runner and are now around 1 3/4 dia and larger at the top. At the head they are about 1 3/4 (square; not angled) by about 1 1/4. i would have made them larger but i'm running outa sealing area. Then better flowing heads will compliment them to some extent as well. My guess is you will save a couple of tenths. you will be a great case sudy for sure. you know exactly what your car runs now, so you can document improvements pretty closely. if you can get low low 11s it would be pretty damn good

Now, is it al worth it??? Duh!

 

Beach, I may be a bit out of my league here in this thread but I'll try to contribute. You may remember I had my heads off during the winter. I cant/wont swap cams and have the heads ported (yet) for other reasons (autocross rules) but I am allowed to do other things. One thing I did was to have the heads shaved .010 and use a thinner head gasket (.029 compressed thickness victor reinz) after talking to the local machine shop/engine builder and a solo2 competitor that is a multi time national champion that just happens to work on vettes for a living. Bumping the cr was a good move and the al heads allow more timing as well as more cr. It helps create more turbulance and efficiancy. Both told me as a general rule of thumb that for every point you add in cr you can expect a %3 gain in hp, more on heavily modified motors as much of this depends on how efficient the motor is to begin with. As for the heads selection I cant comment. But are your valves in your current setup backcut? I would think that it might help your setup if you had that done. Every little bit helps right? If you cant find 50hp in one place, find 5 hp in 10 places.

 

Remember that your low lift numbers, .200,.300,.400 and so on are real important. Your cam sees these twice in a revolution, where it only peaks once.
With a Auto and a SR, the low lift #'s is how I would shop for your heads. While considering the intake port volume as well. If you can come up with out of the box 23* head with numbers at .300 around I220cfm and E160cfm and on up from there. You shall see low 300's at .600 and thats a good goal, with your current settup.
With a 700R, and a 383, I wouldn't have any problem opting for a 220cc head. Your torque converter and 1st gear are loose enough, you'll not even notice a loss in bottom end, but your HP and TQ will improve.

John

 

John and Dennis bring up good points about low lift flow. I have setup an spreadsheet to evaluate avg flow under the lift curve. For our 219 cam i estimate the following share of time vs lift:

Lift %@lift
.05-.1 7%
.1-.2 14%
.2-.3 10%
.3-.4 14%
.4-.5 21%
.5-.6 34%
100%
By using weighted avg across the flow curves of the head you can estimate an average flow with your cam. maybe this will help evaluate various heads. I dunno.

the avg under the curve for the AFR 190s (as published) is 220cfm (they are 224 if you believe the higher flow numbers published in GMHTP Mag). the 210s were 230 and the comp ported version was 243. That;s all i evaluated.

 

Great thread.

I too have been doing some research for my upcoming swap. There is a shop in Bowling Green, KY http://www.totalengineairflow.com/ called total engine airflow. They were mostly a ford shop, but have done lots of chevys. The owner says he can get 290 cfm intake and 230 cfm exhaust out of my AFR 190's at around .550 lift. He says he has done it in the past.

If Jake jumps into this thread, he can give you the number of the guy who ported the miniram for his friend. His name is Bob Jones and he used to work at Extrude Hone. I talked to him on the phone, and he seemed to know his stuff. He said that the Superram flows about 250 cfm stock, and with hand porting and extrude honing, it can get to 300 cfm's, but not more than that. He said the miniram flows around 340 cfm stock, but has an airflow problem after that that needs to be corrected by porting.

I've played around with engine analyzer quite a bit, and the LPE 219 is the best ALL AROUND cam for making power under 6000 rpm. Other cams make more peak power, but the LPE makes the most average power. I just hope that the pc programs are fairly accurate.

By the way, one of the techs that works at total engine airflow has a 2000 Z28 with ported LS1 heads, 228 duration cam, Yank 4400 convertor, and I've seen it run a 7.43 at 92 mph at the local track and the car wouldn't shift into 3rd gear. He says his heads flow 300 intake and 260 exhaust, but I don't know at what lift.

I am also trying to hit mid-low 11's with the ported/extruded superram and ported AFR 190's.

I've talked to GTP, and he says he can get 280-215 easy out of the AFR 190's. LPE refused to give me a quote and said that they don't port AFR heads. Julio at Cartek seems to be the only one who I've seen break the 10 second barrier with the superram. He seems to know his stuff too. My choice would be Cartek or TEA.

Hope this helps some.

[This message has been edited by 89gta383 (edited 07-16-2001).]

 

Interesting information... and it all still leaves me un-decided on what I want to do.

Maybe AFR 190's seriously worked over or the AFR 210's with the race port... and of course Brodix has a few great selections.

I'm too tired right now to think about it.

thanks for the help all.

Beach