class act as always J-Rod

until people spend the amount of timing putting there setup together as these vendors do they will never amount to the same gains. Tony stated he spent 4 hours alone just degreeing the cam to squeeze out the best hp, all of his cyl. have less the 2% leak down, setup a tight quench, ect. he did everything in the book to maximize his setup and show the potential of the heads. i dont see how the average joe who just spends a weekend throwing on the parts can expect the same type of gains.

 

So it seems (to me) that the *out of the box* AFR is a great replacement for any stock LS1/LS6 head but once you start comparing it to hogged out 5.3's or 5.7's (and I am not saying the comparison is a fair one) it is "only" comparable. Maybe "a bit" better with all the same mods and an $850 intake and matched gears. That is until you mill. Then you can pick up some valuable ponies. LGM's numbers (I forget the car) were w/ a 59cc chamber (.45 mill ?) and notched pistons, they sell the heads too. But if you run a (by todays standards) medium/large size cam (or an unknown spec'd G5 cam) you maybe looking at notching pistons, custom size push rods, intake chamfering (to match the mill) and I am uncertain of the strain "geometrically" on the valvetrain and that concerns me.

Probably better to wait out the 225 for some max hp/cam guys. I mean thats the jist of what I picked up anyway. That withstanding, Tony was kind enough to respond to one of my notes on the subject and everything he has said on the board makes perfect sense to me. I will likely get this head similar to Predator Z - (milled fX for 11:1) and not look back since I have a C1 cam...depending on what Edlebrock comes up with in November hehe.

So since this is an AFR head thread and most of us are going to require deck these AFR heads to match/beat cheaper stage 2 heads:
Do we know how much you can mill this head and not have manifold fit issues ?
Is the mill for 11:1 59cc or 62cc (+/- cometics & "normal" deck height varience)
That varience will make a big difference to us medium cam guys.
When do you guys start using custom pushrods ?

Hey ! What "dip" in the dyno is there at 2500 with the LGM's ?
I thought they were the bomb all around (I have no graph)?

Thanks for starting this up J-Rod & nice run at the tuner shootout.

 

These heads seem killer to me. Though no one has seen enough results to make an educated opinion of them. They do seem to flow as advertised. I've been waiting and waiting for the 225's for my motor, but I can't really wait anymore. Last I read, mid August they were supposed to be out. Oh well. But, good or bad, you can talk about all the technical stuff you want yet realictically high peak dyno #'s are what the average person cares about the most lol. If the average AFR setup pulls 420-430 they won't be popular. If it's 470+ like I think most expected then they will sell like like a Brittany Spears **** video.

 

Would the 225's make good power with a full bolt-on stock CI motor running a 231/237?

 

No one knows. They aren't even out yet.

 

From what I hear the 225s will be worth the wait...I'm just as impatient as the next guy, but I would rather have a well developed product than something that was just slapped together to turn a profit.

 

I thought about 2% increase per point of CR.Say 400 to 408 hp and cubic inches has nothing to do with it.And if you pull a bunch of timing out you won't gain that much.I agree with the point that Tony spent 4 hours degreeing his cam and that could make a big difference!!Quench was brought up this is hp maybe better then the compression gain????Like was said there can be 25 to 35 hp or more in a good tune,seems like some dyno numbers are low and some are high. How does it run at the track?A lot of time its the little things that make the difference between a motor that puts out and one that don"t do too good.The guy that switched from the PP heads to the AFR don"t they both flow about 300 at .600 lift and the PP has more CR (1 full pt.) the ony advantage the AFR has really is a 205 port to a 225 or so port,my question is why would the AFR make a bunch more hp???I would like to have seen a before and after track times though! I"m sure Tony at AFR spent a lot of time optimizing everthing to make the 475+hp in his Corvette,as mentioned Tony has been up front from the get go about these heads.I f you want more CR then just mill the heads, if you have v to p issues flycut the pistons,if you want the highest hp #"s then do all your homework.If you think the AFR heads need hand blending then get it done by a porter of your choice,hp is not cheap .I think enough has been shown to see what the heads can do like in Mc-rats car 124 mph in the 1\4 mile not bad!!If you already have good flowing heads then the AFR is not going to be THAT much better,but it is stronger and can be ported out more then the stock casting,but its not a budget head.Lets not BASH it just yet.
Good post J-rod, great idea to put it all in a single thread it makes it a lot easier to follow!!

 

Seems to me that the difference in these heads to a fully stretched stocker is in the mid-lift as well as the streangth. Has more to do with port profiles rather than size and peak .600 and up flow. Like J-Rod was saying about milling the heads and putting a lower lift cam in. I would bet on that combo over not milling with a .600 plus cam. These were meant to pick up where the ported stockers left off. Bring in more torque and higher velocity.

One day when I can afford these bad boys, I will pick up some CNC'd 225s and have them cleaned up by a porter. The 205 flow bench #s seem great, the 225s are gunna rock. Keep up the good work AFR, and thanks for showing people the light LS1tech. I can't tell you how many times I have read, "it's all about the combo."

 

Actually, Tony's car has 3.90s if I remember correctly. Anyway, we can port heads until they flow 450cfm, but the intakes on the LS1 suckass. Also, for a max effort, high revving 346, the Kook's 1-7/8" headers are what you need. Sure they lose low end torque, but for all out top end they work better. I suspect with a cam that is already challenged on the low end, aka T-Rex or a solid roller cam, the Kook's would only strengthen the midrange and top end.

As for AFR, the heads are very nice, but I think the reason many people jump on the bashing bandwagon is because Tony made 480rwhp with a 224/228 cam. Until recently, something like the G5X3 or Cartek X3 cam were the only head/cam packages making anything close to or over 480. Even Tony claimed the streetablility and power of such a "mild" setup. Even I though of matching up such "port velocity" with a great big cam and dreaming about the performance. Hopefully more results will come in. Or those damn 225s will be released. Woo... T-Rex, LSX 90mm, Kooks 1-7/8, AFR 225s... ahh! Building a 400cid engine to turn on a 346. Should be like driving a turbo honda.

 

If a 206CC AFR Cylinder head can flow 320 @ .600" on a stock LS1 bore and a 2.02 valve I can't wait to see how the 225CC version runs.

'There is no such thing as too much air flow, only too much cross-sectional area.'

Mo Powa!

 

Those 225's should be out soon since they are the same casting as the 205"s,what would they flow with a 4.060 bore????Or 4.125???

 

It'll be interesting to see what they flow on a 4.125" bore with a 2.080 valve. I think we'll see some SERIOUS torque out of these stroker motors. The nitrous cars will start to go much faster then too.

 

AFR has done a masterful job with their first product for Gen 3 Chevys. The head casting has a lot to offer. After seeing the results of the first LS1 castings I ported in 1997 I remember commenting that aftermarket heads will have a tougher time outperforming the factory parts compared to the older Gen 1 heads. Lately, I've tested AFR's 205 head as well as their porter version and am impressed with the flow vs cross sectional area. We're starting to creep into the 18º Chevy High Port territory with large valves on larger test bores. As for the 205 head, it flows as AFR advertises. As Tony stated, it isn't designed for use in engines seeking high rpm hp (especially on a dyno) rather it's better suited for those folks looking for more useable low end power in daily driver applications (like mine).
On another note, AFR has done a very commendable job with respect to machining the 205 head. The CNC work is top notch and the seat/bowl transition is very nice for a production part with no hand blending. The samples I've tested were exactly as advertised both in port flow and runner/chamber volumes. As I've mentioned above, the casting has a lot to offer. The head flow of the 205 is very similar to a nicely ported Stage 2 LS6 or 6.0l casting only AFR's head has LOTS of material in the deck area and port walls.
They're getting a suprising number of castings into the hands of quality head porters and the results are starting to appear. The 225 head offers more promise to those seeking power at higher rpm levels on larger displacement engines. I'm being told that they're going to start shipping sometime next month.

Patience,

Richard

 

Nice imformation Richard,nice to hear from you professional head guys.I seen some pictures of the 205 AFR head and noticed the extra material arould the outside of intake \pushrod area,you have to admit the GM casting is kind of light.Will the 225 valve seat cut to a 2.10 valve?I want some AFR castings ported by someone with a CNC program to say 240 or 250 cc for a race only 427.Like to see 360 cfm+ at say .625 or .650 lift. Is that possible??

 

Fastone, I know on Corvetteforum, Andy from A&A Corvette took the bare AFR castings and ported them to 242cc. The heads have insane flow numbers for big cubed setups. I can't find the link currently, but his website has some data on it. From his site: How about 307 CFM at .500" lift and 343 CFM at .600" lift? The port just keeps on going. It eclipses 360 CFM at .700" lift.

TEA also got their hands on one and did:
Lift Intake Exhaust
.100" 68.1 55.1
.200" 141.2 123.9
.300" 207.5 187.1
.400" 261.6 241.1
.500" 304.6 268.3
.550" 323.4 275.4
.600" 341.2 277.8
.700" 346.0 282.2

So, with a rather huge cam and big cubes, the ported heads might enter C5R head territory. Or better yet, BBC territory.

 

IMO the "beef" that a few people have is when fully CNC'd, hanfinished/ported these heads come to $3000 territory. But to those who are able to afford them, they are really promising.

 

well said J-Rod I think AFR completely delivered on what they promised and I can't wait to get a set of bare castings

 

still drooling and bitting at the bit.....
want some.... but must see more results..

 

Hey JakeFusion,you got me druling(spelling??) Over 360 cfm thats insane!!I 've ported some 241 castings to 236 cc and they are hugh compared to stock ports,got exhaust to 90cc pretty big too! All I can say is may the best head portmaster WIN!!!THIS COULD BE GOOD!

 

AFR left plenty of material in the heads so you can make some very crazy sized ports for big inch motors.