Edlebrock or AFR
- Thread starter BlkoutGT
- Start date
SVTurbo 98
Active Member
Paul said:
Here is just a few examples.
This was an experiment done by a popular cam guy.
Here is what I did.
100% stone stock shortblock
9.5:1 compression
AFR 165 heads
Edelbrock Performer RPM (Not the RPM II)
70mm TB and 73mm MAF
1 5/8 L/T with 2.5" exhaust
I used the comp lobes that were handed out above.
286 at .006 - 230 at .050 - 152 at .200 and .373 lobe lift
However, if seefor was as experienced as he'd like to think, then he'd know that this lobe on a SBF core will be 287.8 - 232.1 - 154.7 - .3727. That is the average of the (3) I have personally Cam Dr'ed. Then on a 110 LSA with an IC of 106 and thus an EC of 114. 1.6/1.6 RR
Here is what I get, RWHP & RWTQ.
304 RWHP at 5400 RPM
338 RWTQ at 4100 RPM
From 3500 RPM to 6800 RPM average RWHP was 266 and average RWTQ was 287
It took a spring that was 175# on the seat and a rate of 425# to control it. Thus a SADI core ain't gonna make it.
It wanted to be shifted at 6500 RPM and gear to cross at 6800 RPM.
Idle at a nasty 11.5" of vacuum.
It will NOT pass emissions
It will NOT clear the stock pistons. <=== You WILL have to notch the pistons.
Idle RPM = 850 RPM to 900 RPM
Now, insert a *too big* 195cc Canfield.
Same as above, just swap the heads, cam, and now rocker arms.
I have done this about 1 bizillion times, so I used a cam that I made over 1 year ago so the owner will not be upset if his cam specs surface.
Intake:
292.1 at .006 - 217.1 at .050 - 147.7 at .200 and a lobe lift of .357 X 1.7RR = .607" lift
Exhaust
307.1 at .006 - 231.0 at .050 - 153.5 at .200 and a lobe lift of .349 X 1.7RR = .593" lift
114.5 LSA
113 IC
116 EC
Here is what I get, RWHP & RWTQ.
317 RWHP at 5500 RPM
337 RWTQ at 4200 RPM
From 3500 RPM to 6800 RPM average RWHP was 281 and average RWTQ was 301
It took a spring that was 165# on the seat and a rate of 405# to control it. Thus a SADI core if a titanium retainer would be ok, but NOT recommended.
It wanted to be shifted at 6600 RPM and gear to cross at 6800 RPM.
Idle at a *smooth* 15.1" of vacuum.
It will pass emissions easily
It will clear the stock pistons.
Idle RPM = 750 RPM to 800 RPM
15 more average RWHP in the same range
14 more average RWTQ in the same range
Idles very smooth
Will clear stock pistons
Will pass the smog test
And another example of someone wanting to put afr 205s on a 306.....
With EFI, the 205cc head is not too big. I just love it when I hear this. Those that say it is too big, when did YOU do this? What happens if I put a 1 1/2 header on it with 600cfm carb? Or how about a 210 at .050" cam with say .560" lift? With EFI, the manifold PLUS the cylinder head you'll have 19" of runner. With 19" of runner if you do not have airspeed, you have seriously phucked up.
Back in 1991 I ran a 210cc TFS High port with a TFS truck intake. I did this on a 100% stock shortblock. I used a Wolverine WG-1087 cam. I flycut the pistons by hand. No fancy computer. No fancy suspension. I went 11.44 at 117 at 3280 pounds. I was given one of the first AFM PMS boxes so I could get around the rev limiter. At first I shifted at 6800 RPM and it slowed down over 1/2 of one second. I started to short shift it and it went the quickest shifting at 5800 RPM. So I took the coputer off and gave it back.
With a carburetor, the intake valve timing will be critical. Very critical.
To continue on with this, look at the GM cars. They do the gigantic cylinder head small cam thing from the factory. This stuff is what has been around for years at the high level. When you use a small cylinder head it simply will mask a bad combination. The bigger and better the cylinder head, the more exact the valve timing MUST be.
Plus with the smaller cam, its more driveable and it'll have more engine vacuum at idle for accessories.
Another talking about making a cam for this said engine:
Follow this analogy. I using numbers as a REFERENCE and these are NOT the Holy Grail.
306 cid engine. Holley Systemax II manifold. 1 5/8 or 1 3/4 long tubes. 6500 RPM and below.
You start with the basic AFR165/Canfield 170cc heads. you have a Stage II TFS cam. You now go to a AFR 185/Canfield 195. You'll pull about 7-10 at .050 OUT of it. You'll put lobe lift in it. You go to an AFR 205/Canfield 212 CNC/Victor jr head. You'll pull another 5-10 at .050 out. You'll put more lobe lift in it.
All the while you are delaying the intake events and the exhaust events and consequently the LSA get wider. Smaller at .050. Wider LSA. The thing will idle like a kitty cat.
Another example and I'll mention NO NAMES. But a kid came to me with a pair of cleaned up Canfield 192 (older) heads. That had went to 2.055 X 1.600 valves. Milled to 50cc. They had been ported to 207cc. The flow sheet supplied was 310/210 at .600. A nice pair of heads. He bought off of some message board for 1500.00. A good deal IMHO. He took them to his engine builder and he gets the *too big, no velocity, no tq speech*. He was instructed to sell them. He seen me post over on HC50 and he dropped me a line to see if I could help. He was about 45 minutes away in Perrysburg, Ohio. I went and installed the cam for him.
I did a cam for him, here is what it was:
210/222 at .050, 570/555 lift w/1.6RR, 114 LSA installed on a 111.
The intake & exhaust events were:
IO @ .050 = -6 BTDC (or 6 ATDC)
IC @ .050 = 36 ABDC
EO @ .050 = 48 BBDC
EC @ .050 = -6 ATDC (or 6 BTDC)
Idles at 15" of vacuum. Pulls to 6600 RPM and signs out. Has -12* of overlap at .050. Think what is going on during that time....... .......The heads are so good that more scavaging from overlap isn't required. By my numbers because of cam timing, at 6000 RPM the engine has 347 ft/sec of airspeed. Throttle response and tq are NOT his problem.
Runs 11.50's at 3300lbs in a full weight, a/c-p/s-p/w car.
The last thing that I will address is what guys throw around as velocity.
What is it?
On a running vehicle, how is it measured?
If you measure airspeed at 28" on a given cylinder head, how does that translate into a real world example?
The basic number I always talk about is a std stroke SBC (3.48" stroke) at 7000 RPM is 45" of water. That is not a linear function. So if you are taking some stock GM junk to 7k, why even pay attention to the 28" numbers? They are meaningless?
This is part of the reason that an EFI car will take more cylinder head. The manifold is a restriction. Thumper I KNOW you have loads of flow bench experience. Flow a head at 28". Bolt the manifold to it. The flow goes DOWN while the column of water goes UP. This is showing you a RESTRICTION. Imagine of an engine was operating up at 35" to 40" of water (like most 306 with aftermarket manifolds are at). The flow will go in the toilet. The column of water will get very unstable because of turbulance or ther airspeed is simply too high. As the restriction is taken away, things get better. hence the bigger/better head.
For every CID -AND- a given RPM range, there IS the point that the head can get too big. This is because the cam can only get so small before the CAM is the limiting what the HEAD can do to the point that POWER goes down. The common mistake is with a larger head you need a bigger duration cam. If you do this, you'll have a gutless turd.
With my experiances this is right on par. Btw there is a ton of different ways to build engines and make good power. Good luck with whatever you decide!
SVTurbo 98
Active Member
Paul said:
The cam guy is Jay Allen.
And this info is at sbftech.com
http://sbftech.com/index.php/topic,4362.0.html
http://sbftech.com/index.php/topic,1784.0.html
Trickflow.GT
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SVTurbo 98 said:
Reading this whole thread is hilarious. There is simply to much internet hype around AFR, and stock port location heads in general. And for the people referring to Trickflow twisted wedge heads as a "Canted Valve Head" you are sorely wrong. Trickflow highports are a canted design, NOT twisted wedge's.
And as for being scared about buying parts for motors involving heads with superior chamber design and valve angles/locations that is an absolute crock. If you motor builder cannot order a set of probe pistons to clear a twisted wedge head he should not be building motors.
And as for SVTurbo 98...its good to finally have another person in here who realizes there are better things in life that SADI core letter cams and AFR heads. Heres a shout out to all my other SBFtech bro's.
Modo...you should just go back to corral.
-end rant
modo
Well-Known Member
Trickflow.GT said:
What really is hilarious is that your feelings are hurt from reading a thread on the internet. So please clarify this internet hype you speak of. There are plenty of real world numbers that backup that afrs are good heads and work. Hell I went 126 mph with a set of afr 165s. How fast have you been with your trickflows? My current little 205s have been 144 mph. Have YOUR trickflows been that fast? Probably not. Now are they the best head for every car? no...
Did you not read the title of the thread? edelbrock or afr. does it say afr or trickflow? no
glad to know i bother you
