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351 4v Intake question, can this be right?
#1
OK, putting my closed chambered 4V heads on my 71 M code Mach tomorrow. I repainted them the proper dark Ford blue after it was pointed out that's the correct color. After comparing the weights of the standard 4V intake with an Edelbrock Performer 4V intake, I decided to go with the Edelbrock. I noticed that the ports of the Edlebrock 4V Performer are smaller than the ports of the heads, the original cast iron intake has the same size as the heads. Shouldn't the Edelbrock 4V ports be the same size or is it not an issue?


.jpg   Intake.jpg (Size: 46.71 KB / Downloads: 180)
.jpg   Intake2.jpg (Size: 96.3 KB / Downloads: 179)

Jim

M code 71 Mach 1, 351 4V Cleveland, Ram Air (not factory), C6 Trans, 3.5 rear
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#2
The ports on the Performer are intentionally smaller to provide better flow velocity. It will not be a problem. If the port were smaller than the manifold it would create turbulence at the port inlet which would be a problem. You could port match the manifold but would not likely gain much performance.

Some performance/race manifolds like the Edelbrock Victor are quite a bit smaller to provide more meat for port matching.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
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#3
On my old motor I used a gasket set to port match both my heads and intake. Put some blue machinist die on the head and traced the gasket same with the intake then took die grinder to them and matched them up. Not sure how much I gained but figured it couldn't hurt.

Kevin

1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

[Image: 28ivsix.png]




                                                                                             
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#4
droptop73;170988 Wrote:The ports on the Performer are intentionally smaller to provide better flow velocity. It will not be a problem. ...

Thanks Jeff, that's a load off my mind!

Those puppies are going on tomorrow and off with the 2V heads that the prior owner had put on it.

   
.jpg   Intake3.jpg (Size: 135.22 KB / Downloads: 160)

Jim

M code 71 Mach 1, 351 4V Cleveland, Ram Air (not factory), C6 Trans, 3.5 rear
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#5
+1 the smaller ports keep them from loading up as easily.

COOL PROJECT!
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#6
Just a rhetorical question, but why would you want
to use a smaller/mismatched intake on a Cleveland?

mike

[Image: 1_11_11_13_11_50_27.png]
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#7
to compensate for the oversized ports at lower RPM's (in theory I suppose)

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#8
Exactly, throttle response comes from flow velocity not flow volume. When an air column is moving faster it fills the cylinder better.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
  Reply
#9
I didn't notice any valve stem seals?

[Image: Image3.png]
Jim
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#10
They're there... the blue things inside the springs.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
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