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Edelbrock vs. CHI V3 & CHI V2
351C Aluminum Head Comparison
 
 
A few items to consider in comparing the heads.
Both heads were flowed on a Superflow 1020.
The Edelbrock heads only had the seats roughed in with a 3-angle
cutter, seats were not finished ground. Also the seats needed to be
blended.
Edelbrock has 2.055" intake valves and 1.600" exhaust
CHI heads have 2.150" intake valves and 1.650" exhaust
I think the CHI heads have the valves seated to low in the head,
it takes a
good .100"-.200" valve lift to get "out" into the chamber.
This may contribute to the poor low lift numbers.
I don't think the Edelbrock heads could fit a valve larger than
2.100"
My observation is the Edelbrock is the head for lifts below .550"
lift. For all out power, bigger lift cams, the CHI looks to be the better
choice.
Due
to comments I have received about my observation above, I am adding this extra
comment.
I am leaving the original statement above, but would like to add
that
this comparison started out with the 3V heads and the Edelbrock. As you
can see the 3V did not flow as well as the 2V, this was due to the company who
originally assembled these heads did not radius the intake seat area. You
can see that the flow numbers on the 3V are a ways off from the Edelbrock in the
usable range of most small cams. Ex. side can be helped with cam
selection. At the time we did not have the 2V heads and the flow numbers
were changed later. I neglected to reconsider my opinion I originally
made.
If I
may give a new observation, it would be obvious that the choice here would be
the CHI head. I know the 3V flow much better than shown above if prepped
properly.
Hopefully this did not cause to many people to think "what in the world is he
thinking"
It is
a case of adding info to the web page and not re-looking at what was all said.
I would like to machine larger valves into the Edelbrock and see
how it would compare,
but the exhaust side suffers.
| Valve Lift |
Edelbrock Intake |
CHI Intake
V2 |
CHI Intake
V3 |
Edelbrock Exhaust |
CHI Exhaust
V2 |
CHI Exhaust
V3 |
| .100" |
60 |
66 |
55 |
52 |
59 |
55 |
| .150" |
98 |
101 |
76 |
75 |
79 |
74 |
| .200" |
136 |
134 |
101 |
95 |
99 |
93 |
| .250" |
172 |
166 |
128 |
113 |
120 |
112 |
| .300" |
205 |
195 |
157 |
130 |
140 |
132 |
| .350" |
225 |
222 |
188 |
145 |
158 |
152 |
| .400" |
240 |
246 |
219 |
155 |
171 |
170 |
| .450" |
248 |
266 |
249 |
161 |
181 |
182 |
| .500" |
254 |
280 |
276 |
165 |
190 |
193 |
| .550" |
256 |
292 |
298 |
168 |
198 |
203 |
| .600" |
257 |
284 |
315 |
170 |
207 |
213 |
| .650" |
258 |
282 |
324 |
171 |
214 |
221 |
| .700" |
259 |
|
315 |
171 |
223 |
226 |
The light gray cells shows the better flow, the V3 heads are not
included because we are
trying to compare apples to apples. As you can see the low
lift numbers on the V2 heads are much better, this is because the casting we
received had a radius from the top of the seat to help allow flow at the low
lifts. The V3 heads did not received that radius.
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