Edelbrock heads Vs. Stock 291-c's the unequivocal truth - Pirate4x4.Com : 4x4 and Off-Road Forum
 
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Old 11-02-2006, 11:57 AM   #1 (permalink)
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Edelbrock heads Vs. Stock 291-c's the unequivocal truth

Here is a set of Edelbrock Performer RPM heads for the AMC V8 vs. a set of untouched 3196291-c heads (52cc dogleg heads made in 1970). You will see the ports on the Edelbrock heads are smaller in size when compared to the 291-c heads in some areas, larger in others but offer a smoother port. The Edelbrock's combustion chamber is superior to the stock 291-c's chambers. Edelbrock claims these flow #'s




Now we are flow testing these heads as I speak and will post up real world numbers. We will also be doing very basic port work and re-flowing the heads.


Now here we show the port size differences...they are slightly off. Its hard to measure these accurately with a caliper :?:










291-c heads are the sought after 52cc chamber heads found only in 1970 360,390 and early 71 401's. The Edelbrock heads are 54cc and offer better and cleaner flowing chambers and come complete with stainless steel valves, guideplates, studs, 115lb springs and can handle up to a .580 lift camshaft. they are aluminum and can handle a slightly lesser octane even with a bump in compression over the stock 58CC dogleg AMC heads found in 1972-1991 (all AMC V8). Nice setup for around 1600 bucks! I will post up the flow number increase as well as pics of the simple port matching we will be doing.
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Old 11-02-2006, 11:59 AM   #2 (permalink)
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AMC hobby racer Ken Parkman posted these flow numbers on stock heads. Edelbrock's out of the box numbers rock the stock! Stock heads are said to outflow the Edelbrock heas when you overport and sleeve ...severe racing applications only.
291 090 502
.100 71 74 70
.200 127 156 143
.300 179 201 192
.400 209 219 213
.500 217 226 220
.600 222 232 228
.700 228 238 236
Exhaust:
.100 55 56 59
.200 107 112 113
.300 135 141 146
.400 142 145 150
.500 145 149 152
.600 145 150 153
.700 145 151 153
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Old 11-02-2006, 12:18 PM   #3 (permalink)
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Cant wait too see the ported numbers for the 291C's!!!
Great info!
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Old 11-02-2006, 01:17 PM   #4 (permalink)
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Crappy gasket but it is correct for the dogleg head blue prints. Lots of room for porting.
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Old 11-02-2006, 05:55 PM   #5 (permalink)
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MC, can the edyl heads be opened up to the size of the 291c's? I have the edyl heads on my 401, but didn't open much, if any. Actually with my cheap ass fenderwell headman headers, they were pretty close to matched up. I was looking at getting some new higher quality ones. Got any suggestions on better headers with bigger doglegs too?

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Old 11-02-2006, 07:34 PM   #6 (permalink)
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Yes they have extra meat there to open them up quite a bit. Since they are aluminum they can be over poerted and sleeved pretty easily. The port size and location has seemed to change from the first batch.
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Old 11-04-2006, 03:13 AM   #7 (permalink)
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Matt buddy..........
I have a hard time understanding the Empirical data presented by the Parkman flow experiment.
1. Did he address the what are they...3&4 or 5&6 cylinder heat crossover interconnection between the exaust ports?
2. Does the Elderbrock heads have the same passages cast into them?
3. Flow testing is done at ambient temperature, I would think high temps would skew the actual "on engine" flows. As well as header length and pulses.
The way I figure it the head flow is disrupted between 1 cylinder each on each head. Is there a way for you to address it?

For my own I welded closed the passageway in the manifold, I want all cylinders to be independent of each other.

I will post some pics of my "on Bridgeport" porting and the exact header flange pics versed the waggy stock gaskets as you have posted above.

Gotta run,

Jeff
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Old 11-16-2006, 11:50 AM   #8 (permalink)
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Intake:
291 090 502 Edel (true numbers)
.100 71 74 70
.200 127 156 143 125
.300 179 201 192 212
.400 209 219 213 235
.500 217 226 220 266
.600 222 232 228 243 (bad turbulence
.700 228 238 236
Exhaust:
.100 55 56 59
.200 107 112 113 98
.300 135 141 146 130
.400 142 145 150 156
.500 145 149 152 174
.600 145 150 153 184
.700 145 151 153 (Edel @ .650 lift .187)

The ratio was 70% Exhaust/intake. Best ratio being 82-83% for a good race head. These heads with some smoothing and valve unshrouding should hit just under 300CFM. Their is alot of meat to be taken away on these yet and as you may already know we havent touched the castings. This is an out of the box flow test. They actually flow BETTER than expected but 6CFM less than advertised on the exhaust at .600 lift and 8CFM more on the intake at .500 lift. They have some work to be done for a race head but for street or trail this is an awesome set of heads.
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Old 01-03-2007, 09:15 AM   #9 (permalink)
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3216090 head flow #'s

We flowed a set of stock 3216090 single rocker dogleg heads and got these numbers

Cylinder head chamber volume 59.8cc
Intake valve 2.025 (stock)
Exhaust valve 1.68 (stocK)

Lift/Intake/Exhaust
.200 139 110
.300 184 134
.350 199 146
.400 207 148
.450 213 149
.500 217 152
.550 219 154
.600 221 155
.650 222 154

Heads were boiled and blasted before flowing
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