87cc edelbrock heads porting
 

Are there articles videos or general guide lines to porting these heads. Just looking for 315 cfm or so. Thanks Rod

What intake manifold will you be running?

What size motor are they being bolted onto?

How much HP are you looking to make?

What's the weight of the car?

What's The rear gearing of the car?

How much does the car weight with you in it?

.030 455 flat tops ,eddy rpm intake 1961 tempest 3700 # ,overdrive trans 3.89 gears something like the old faithful cam. would love 600 hp

You will need 290 cfm to hit that 600 hp target, not 315 so that makes the port work needed a tad easier.

With iron D ports that I ported to 280 cfm for a 10.75 comp 400 I have made a dynoed 580 hp, so 600 hp with 290 cfm and the far bigger port volume of the E heads should be cake!

Basically all you should need to do porting work wise with those is to do a light bowl blend job, cut back the head bolt boss that sticks out into each runner by 1/2 of what's there now, and raise the roof from above the crown of the short turn by .045 and then blend that to a RA4 gasket height at the flange.

The wild card here is the air flow limit of the rpm Intake.

real world build tested at track 1962 catalina .030 455 87 cc ported e heads probably flow around 300 10.5 to 1 comp bullet hyd roller cam 234 238!@.050 600 lift rpm intake 1000 cfmquick fuel carb 10 inch converter 3.42 gear thru full exhaust drag radial rear tire has gone 11.68 @115 street car. weighs over 4000lbs

bet that big SOB has surprised some newer cars at the stop light.

I made 600 h/p with 2-455 engines using Dave's stump puller cams. KRE d-port heads. I tried an RPM intake and Torker 2 and both were the same. I settled on the Torker 2 intake. Engine also made 600 torque.

OK, the subject of the KRE head has been brought up. Now relating the difference in intake runner volume between the KRE head and the Edelbrock head. The Edelbrock head having the larger intake runner volume.

I believe it was steve25 years ago that made a statement that one would need more intake duration as the runner volume increased to make the similar amount of power at the same or similar peak power rpm. Or something to that affect.
I don't remember how many degrees increase he mentioned, not much though.

As an example... I have dyno sheets for two different engine combos that are so similar you might say they were the "same". One with unported KRE D-port heads and another with 87cc Edelbrock heads with a slight 'clean up' only, almost stock. Both used Crower hyd flat tappet cams. The KRE combo made 502 hp at 5300 rpm with 231 degrees intake duration. The Edelbrock combo made 509 hp at 5300 rpm and used 236 degrees intake duration. This might support the statement above about runner volume and increased duration.

A fwiw, Tom Schlauch has often reported with his combos that a 455 with KRE 290 D ports, 245 degree intake w/ 252 degree exhaust & .4000" lobe lift hyd roller cam were in the 550-600 HP range depending on intake and carbs.


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Imo more running volume/flow will require less cam not more.

Steve were these two examples ran on the same dyno?

No Paul they were not the same dyno. I wish they were.

"Imo more running volume/flow will require less cam not more."

Ok, that is the opposite of what I stated. Thanks for the input because I'd sure like to clarify the situation.

And now that I think about it I believe Tom S has mentioned Joe Sherman said the better the head the less cam needed, or something like that.


Other opinions ?

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Stated: "..... something like the old faithful cam. would love 600 hp"

The old faithful hyd roller has 236 degree intake duration.

For interest, a dyno proven combo as an example. And yes different dyno's will not have the same results :)

4.250 stroke / 474 CID
87cc Edelbrock heads ported.

rated 312/230 at .600"
rated 315/236 at .700"
tested at 28"
Claimed only about a 220cc intake runner volume.

9.95 compression.
Victor intake / 850 cfm carb
1.750" headers
Comp hydraulic roller cam with 242/248 at .050".
.540 / .562 lift w/ 1.5 ratio
110 LSA

578 HP at 5500 rpm
588 ft.lbs TQ at 4700 rpm

( side note... more valve lift would of helped take advantage of the heads flow numbers. Also the obvious, more compression )


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KRE has achieved 545 hp with unported d-ports. There are a few dyno sessions shown on FB.

OK, and what was involved, and presume more than 231 degrees duration ! How does that relate to more or less camshaft vs intake runner volume ?

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Running port velocity.
In most cases higher velocity will reduce cam size for a set displacement and RPM.
An exception, when velocity is extremely high for a limited CSA - like Super Stock etc.

A nice formula -
FPS = ( Flow_CFM * 2.4 ) / Average_CSA

But a running engine is not a flowbench. So how does the engines piston demand interact with componets (intake, head, cam)..??

Ok, I found this.....

"Intake Runner Volume - A larger intake runner volume allows more air and fuel to flow through it. However, the larger "tunnel" will slow the velocity of gases moving through it. Smaller intake runners would speed up the flow of gases through the cylinder head and increase throttle response and torque."

Back to square one.
Involving a increased velocity. Is this then viable... one would need more intake duration as the runner volume increased to make the similar amount of power at the same or similar peak power rpm.


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A bigger port will need to be spun higher and faster :D

Exactly, more CSA will tolerate and prefer higher. Then the optimal valve lift curve shifts as well.

Here are some theoretical cam examples for two different target velocities.

463 Pontiac
5500 RPM
1.65 Rocker.
Hyd Roller specs.

300 FPS
-----------
295 @ .006
242.5 @ .050
167.5 @ .200
.659 valve lift.

310 FPS
-----------
291 @ .006
239 @ .050
164 @ .200
.651 valve lift.

Ok in in layman's terms... the Edelbrock head needs a bit more duration.

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