Okay i am puttin together a 468 at about 11-1 compression with about 8.2 DCR, I am thinking about using UD's solid 288/296F12 cam. this is in a 71 firebird mostly street, with a dougnash five speed(and steep gears) I already orderd and have the edelbrock oval port 100cc heads, i also have a oval port air gap, Now after talking with AFR BB head designer, I am almost sold on going with their 305CC Rectangle port, and sending my edeljunks back to jegs and exchanging my air gap for a rectangle port. I was already going to spend about $350 to have the edelbrocks touched up sos that would already be about $2050-2150$$$ which include angle milling them to about 102CC.
The guy at AFR told me that his heads have the same velocity or better than the edels and that they flow way more. Plus I have heard that the edelbrocks sometimes have poor valvejobs? So my main question is, will i have the common "no torque" on the bottom end with a set of very small 305 rectangle port heads? what would you guys do? I want the best but I am on a tight budget, this is going to make me have to wait to put my bottom end together! but it sounds well worth it! graemlins/clonk.gif graemlins/clonk.gif

[ 03-03-2003, 07:53 PM: Message edited by: cody ]

I don't know about the 305s but I bet they will work real well on a serious street or bracket BB. There is nothing wrong with the Eld heads but there is a good chance on a serious engine the AFRs will work better.

I cant speak from experience but... have researched the oval/rect issue with some
head designers/porters, machine shops. (I plan on swapping to a small rect. like
a 310 Canfield on my 502 in the future) So before anyone says I'm full of it:
I've talked to David Vizard and he told me that I would be find, wouldnt hurt my
mid range torque (625@4500), and would wake my engine up on the upper end.
I've also talked to Brian @ TEA, one of the best cnc porters in the country, he
also said basically the same thing. Canfield said the same thing too.
One thing to note is that with the bigger head comes lots more flow - cfm.
I dont know what my 049 ovals flow, with bowl work, but lets say around 300cfm@700.
Now you take a good small rect. head like a 310 Canfield (or AFR) and look at
the flow #s and notice that theses heads (cleaned up bowls) flow 300+cfm @ 400 lift.
This means that the air speed is about the same per cross-section of the intake runner,
just because the heads flow so much more air - 400+cfm@700 (with TEA cnc work)
Air speed is really up by 25%+/- @ peak lift. Also low/mid lift #s are up too.
These are killer numbers, since they move so much more air then a mild oval port
the air speed has to be up.
This was all said pertaining to my 502, but I'm sure it
would pertain to a healthy 468 too. Sound like your engine will make 600+hp easy,
thats why I'll suggest you swap to a good single plane, like a Dart, its a good intake,
with long runners for mid range torque. You wont need anymore low end then you'll
already have, especially with a 5-speed!
I say go for it, but match the killer flowing heads with an intake/carb (850DP min.)
that can feed it and a good exhaust too - 2" headers & 3 1/2" exhaust with good flowing
mufflers. My 2 cents worth.

Thanks for that post! graemlins/thumbsup.gif Well the edl's are 290cc with port work about 295CC, the AFR's are 305CC, so it isn't much more, My main concern is if the AFR's are that much better? I am going 2 inch super comp hooker headers and 3 inch exhaust with an X pipe w/dynomax utltra flows. As far as a carb. I was going to go with a 830 HP, but might consider the 950HP, I am heavily considering the AFR's but there flow numbers are only about 20cfm better than slighly ported Edl's which is significant but not all that much. BUt AFR's seemed to be unmatched and teh best, so i guess i can't go wrong, I am not sure about a single plane however, but some suggestions would be helpfull, i do want some torque, i am running a doug nash five speed, with a 3.27 first/1.1 fifth with 3.08's in the rear, someone told me that was about a 4.00 final drive? whaddya think? This is a street car, so i do need the bottom end torque and especially throttle response! It will be nice to have 600HORSE! still got some money to save!! that carb,headers,alm.radiator,and a couple of other parts are gonna add up!Your combo seems to be pretty nice,any more info is good graemlins/beers.gif

Check these heads out: http://www.rayfranksent.com/page5.html My set of 320`s flowed 408 cfm @ .700 with only a small amount of bowl work, no serious porting. The intake ports are a large oval port.The cool thing about these heads is that they use a permanent mold casting. The heads are identical to the machined mold. This makes them basically CNC ported out of the box. I don`t have any dyno #`s or timeslips on my 496 yet.I have driven it once though and can light up my 31* 18.5" hoosier quick time`s at will at anything over 3000 rpm. It is a torque monster. These might be a bit large for a 468, I don`t know. They are awesome heads for a 496 or 502 though. Brent

Here is a post that i found, where TOny the AFR guy is talking about some of this stuff(long) long post but very interesting, anybody translate? here is what he says;

"In regards to the upcoming BBC Ovals....two versions to be released. A 270 cc "as cast" version that flows 330-340 CFM intake/ 285 CFM exhaust...(these are big numbers for a port that small, especially one that is not CNC ported) The larger version will be CNC ported with a finished volume of 290 cc's. This version will have stronger low and midlift flow and peak numbers exceeding 360 CFM as early as .550 lift! Exhaust flow will be in the 300-310 vicinity....good candidate for a single pattern cam for a non-nitrous guy. Killer head for most "street" applications as well as serious compression motors in the 400-460 cubic inch range. Should easily put up close to 750 HP in that kind of configuration. We will have some dyno tests on all this good stuff in the not soon enough future. My best guess on the availability of both products would be sometime late spring to early summer"

then to go on about the rectangle ports he says;
"To answer your question and be as un-biased with my response as possible, I will just state facts that I know to be true. First off, no other BBC head is built as strong as the new AFR casting...anyone that has seen one could attest to that. Our head deck is .750 thick!....that is insane....you could angle mill .150 off of it and still have well over a half inch. For comparison, a Dart Pro 1 has only .400 to start with....a mill or two later to bring up the compression level and this becomes a head you wouldn't want to use in an engine that sees extreme cylinder pressure (ie. blower, nitrous, turbo etc.) The Dart Pro 1 line is one of the worst offenders as far as strength and "build quality" so to speak, but none of the other manufacturers have much more than about .500 of deck material. As far as flow is concerned, the most efficient and highest flowing of my competitors heads would be the CNC Pro 1 Darts, unfortunately, the castings have there issues as discussed above. The new AFR BBC head has slightly more peak flow numbers (about 10 CFM @ .800 lift) but has a significant advantage in low and midlift flow (10 - 20 CFM). I am personally a fan of strong low and midlift flow and I like a cylinder head that flows big numbers early. In designing the new AFR head, I made a decision on combustion chamber shape that favored the "curve" versus big peak flow figures (the "bragging right" numbers at .800 and beyond...) As much as I would have liked to advertise even larger peak flow figures, I knew the version of my head that flowed 10 CFM better across the curve would outrun the same head that had a 10 cfm higher peak number. Reality check here....even if you run an .850 lift cam (and for most of us that is not on option for valvetrain reliability issues), after .020-.025 valve lash removed...another .010-.020 removed from stud flex, pushrod flex, etc., that leaves about .810 at PEAK lift where the motor is for a nano second. An engine with a camshaft that size would spend a bunch of time in the .700 lift range and obvoiusly spend a fair amount of time both getting there and leaving there (low and midlift flow). Anyway, I think you get my point.

I just looked at my CHP where todd mckenzie did a mild bowl job on the GMPP(same as edlebrock) heads, i compared these numbers with afr's 305cc heads and the 305's had about 15-20 cfm flow all across the board(about the same flow from 100-300 lift)they have about 35-40 cfm more than the stock GMPP w/out bowl work. seems like a pretty good difference,and the AFR's are only about 12CC bigger. plus the edelbrock's weren't too impressive, the casting looks poor? I wasn't gonna go for a full port, just a bowl and a little cleanup. but maybe i am just trying to convince myself? graemlins/clonk.gif :confused:

posted 03-04-2003 09:40 PM
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OKAY, I DID IT. I sent the edelbrocks back to jegs today, I really hope these AFR's are gonna be worth it. I had to spend about 65 dollars to send them back! I only want to buy heads once, so i figure i can't be going wrong with afr's! Once i get my credit i will be ordering the heads. Tony does seem like a nice guy, he actually takes the time to answer every question, and doesn't give you the feeling that he is impatient or doesn't have time. He is a big help, the only suspcious thing is he couldn't say anything good about any other heads. But I guess he is confident in these AFR heads! now to figure out if i want a single plane or dual!!

Let us know how they work. I am interested in building a 454 for my '67 and I've had my eye on the AFR's since they annoumced a BBC version. They have a very good rep among the SBC crowd. I'm glad I saw the posts about buying dirctly from AFR. I didn't know about the distributors using cheap components. I want to use the performer rpm air gap if it a good match to those heads.