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-   -   intake swap (https://forums.maxperformanceinc.com/forums/showthread.php?t=886056)

i82much 06-27-2026 08:16 PM

intake swap
 
65 goat, 505 ia2, 87 cc e heads and doug's round port headers. 3.54 gears, 28 inch tire, ultra wide muncie (2.98 first gear). OF 1.0 cam and 1.5 rockers.

street car, running rpm intake currently. 800 avs2 which i LOVE because the annulars rip in the mid range.

anyway i have a t2 and a one inch open. my car is running really well so i have to mess with it. worth swapping to the t2 and open?

Steve C. 06-27-2026 10:09 PM

Not revelat to your situation, especially with the cam in use.
But here for interest only, my dyno results when I first put my 505 together....

Testing with the Performer RPM intake and also the Torker II intake.
As stated it was a Toker II that I borrowd.

https://forums.maxperformanceinc.com...owed+Torker+II

The Victor intake is the top dog ! Later we never bothered to test other intakes on it with further dyno sessions.
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steve25 06-28-2026 06:49 AM

Please answer what you can of these.

What in particular are you looking for out of your combo that you’re dissatisfied with now?

How wide is your torque band now that the motor pulls the hardest in, is it 2500 rpm wide or less?

How much does the vehicle weigh with you in it?

What track times does it currently run?

Steve C. 06-28-2026 11:01 AM

Previous Info posted from 2016....

Older style Edelbrock 87 cc heads, ported by CVMS to around 320-ish.

Note, not a 505 but will be of interest...

"A torker 2 is very street friendly at least in my combo..compared to a rpm intake ..my old torker 2 with a Wilson tapered one inch spacer had more bottom end torque , 60 footed quicker and felt more responsive on the street."
ta man
466 cubic inches
KRE 310 cfm heads.
Torker II w/ HP950
OF 2.0 cam ( 235/245 @.050")


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i82much 06-28-2026 11:12 AM

Yeah one of the reasons i want to play around is to see if my heads actually had any port work done ... long story!!

i82much 06-28-2026 11:13 AM

i seem to remember SD performance used to have a nice intake dyno test on their website but i can't find it anywhere.

Steve C. 06-28-2026 11:58 AM

Dave Bisschop intake dyno testing....

474ci engine / 290cfm CNC ported KRE D-port heads with 10.2 to 1 compression on 91 octane fuel with a 236/245 duration hyd. roller cam.

Intakes gasket matched to a 1233 Felpro gasket, each intake was mocked up to make sure port alignment was correct and each intake had the water crossover removed.

Stock iron factory intake with Q-jet carb.
515hp @ 52-5300rpm and 575 lb/ft @ 4000 rpm.

Factory cast iron with the CNC machined plenum with Q-jet carb.
527hp @ 5300rpm and 579 lb ft @ 4100rpm.

Edelbrock Performer RPM
541hp @ 5400 rpm and 591 lb ft @ 4000 rpm.

"The purpose of this test was to see how each intake behaved in this particular engine combination. Other combo's can and will have different results but I felt this info would be interesting to our customers to look at and may be helpful in parts selection"
Dave Bisschop


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steve25 06-28-2026 12:00 PM

Well if the heads are off the motor and you can’t find a shop to flow test them then At least CC 2 or 3 intake ports and compare them to the stated stock port volume.

Or if there once again off the motor and you have a set of inside snap gauges and a dial caliper I can tell you where to check for size and what size you should have to get in well in the ball park of a given level of intake or exh flow.

I am currently porting a early set of Edelbrock high comp heads so you might want to take advantage of my offer if your inclined to.

i82much 06-28-2026 12:05 PM

Thanks Steve. Heads are on the engine. My crossover is separated so it looks really easy to pop off the intake, looks like i can just leave the distributor in place and pop it off, measure the ports with a caliper.

I get my kids tomorrow and they seem to like doing this stuff with me, maybe we'll head out to the shop tomorrow and see what we find out!

Steve C. 06-28-2026 12:29 PM

Measure the height on the intake ports....

Skip Fix has mentioned his 320 cfm CNC KRE ported E heads had an intake port tall enough there was no way the Torker II intake would seal.
He added aluminum to the top by welding then a clean up mill.
Anything much bigger than the FelPro 1233 gasket started getting questionable on seal for a Torker II intake.

The FelPro 1233 intake gasket has a 2.200" port height according to my records.

SD Performance CNC 345 cfm heads in use here and noted the work done to the Torker II intake to accommodate them.......

"...the manifold ports were too short for the CNC ports in the heads and required TIG-welding raised port tops in the intake, which then needed to be machined flat and port-matched."

https://hips.hearstapps.com/mtg-prod...75&format=webp


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steve25 06-28-2026 02:23 PM

That 515 hp back in post 7 means the stock iron intake was passing on average 250 cfm@ 28”.

Steve C. 06-28-2026 03:55 PM

And that goes right back to the topic of Rocky Rotella and Jim Hand testing and the subject of total air flow thru the intake system in this thread.

https://forums.maxperformanceinc.com...+Hand%27s+book

Jim Hand reported to me that a stock intake will flow about 91.5 to 92 % of a head at 250 cfm.
But I don't recall if that included the 5-7 % reduction with the carburetor.

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Steve C. 06-28-2026 04:41 PM

Use that 515 hp from SD Performance and on average 250 cfm@ 28”

Jim Hand presented this formula in his book for prediction of horsepower based on total airflow tested at 28".
Presuming everything is optimized to take advantage of the total airflow available.

hp/cyl = .26 x test flow.

.26 x 250 = 65 hp/cy

65 x 8 cyl = 520 HP


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steve25 06-28-2026 04:54 PM

515 hp / 8 =64.375 HP per cly.

Then we need air flow @ 10”

64.375 / .43=149.709 cfm.

To convert air flow at 10” to 28” multiple by 1.67.
149.709 x 1.67 =250.014.cfm.

Steve C. 06-28-2026 05:46 PM

Jim Hands's post here on PY regarding formulas....

https://forums.maxperformanceinc.com...d.php?t=413050

Another one...

It predicts a normally aspirated engine's horsepower potential based on intake-system airflow.
The net cfm airflow delivered 'at the valve' thru the carb, intake manifold and cylinder head. Not the cylinder head cfm flow itself.

Horsepower = 0.25714 x cfm at 28" x number of cylinders

There are some caveats involved. Actually reaching the predicted power level requires the engine to have the right compression, the right cam, a tuned exhaust, and a nonrestrictive carb and intake manifold. The combined lift generated by the cam lobe and rocker arm should equal the observed lift on the flow bench needed to achieve the desired intake port flow, plus a good exhaust port flow. Etc, etc.

( Information provided in this post does not represent any endorsement. And unless specified it is not based on personal experience and is offered for general interest only )


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Steve C. 06-28-2026 06:06 PM

Side note...

In Jim Hands formula I posted above the .26 number is for testing flow at 28"

For the other test pressures he uses these numbers:

25" = .27
15" = .35
10" = .43

These numbers were furnished by Harold Bettes at SuperFlow

EDIT: All of Dave Bisschop's Edelbrock CNC ported cylinder heads are flowtested at 28"

Here is his 315 cfm head - https://www.sdperformance.com/viewPr...p?productID=37

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Region Warrior 06-28-2026 08:31 PM

Like my girlfriend says never hurt try something different...

Steve C. 06-28-2026 09:02 PM

"Older style Edelbrock 87 cc heads, ported by CVMS to around 320-ish"

A rhetorical conversation....

One popular calculator suggests the horsepower for that amount of cylinder head flow is 607 with a RPM Range of 5,106 to 6,606 for 505 CID.
That number is without the intake manifold nor the type of intake, single plane or dual plane. Nor does it factor in the 4.250-stroke crankshaft.

Another calculator suggests only 275 cfm at 28 inches with 505 cubic inches at 5500 rpm at 100 % VE.
Again no stroke length involved in the calculation.

Nor does this even involve intake runner volume that influences how the combustion chamber is filled during the intake stroke. Bigger is not always better.

Steve C. 06-28-2026 09:22 PM

462 CID with 4.210" stroke.
313 cfm old style Edelbrock heads at 0.600' lift.
580 hp at 5800 RPM with a Performer RPM intake
XE 254 at .050" sold roller.

(600 hp with a Victor intake at 6000 RPM )


Knowing you need 8-10 degrees more duration for a sold roller, not far off from the Old Faithful 236 degree hyd roller.

This, and a 505 will eat up the amount duration !

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ta man 06-29-2026 12:30 PM

It is always worth it to try. My engine still has a Torker 2 on it. I have tried an Rpm and a Northwind over the years and went back to the Torker 2. Mine has had a bit of work to it by Derek Stewart and later by Dave Bisschop.


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