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Edelbrock streetmaster intake porting

July 4 2006 at 6:43 AM
Nick  (Login rcodecj)
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I have an Edelbrock streetmaster intake that is unported. I would like to send it to a professional porter to have ported. I am planning on running Edelbrock heads. It seems to me I would want to send the intake and heads to the porter, or would a template of the head be good enough? It also seems to me that you would want to know what the heads flowed in order to port the intake to match. If the heads were ported, then youd want to port the intake more right? Also any spacer that would be used on the intake would need to be included with the intake to port it, right? Does anyone know how much airflow a streetmaster will flow after porting? Im wondering at what point the streetmaster would not be able to be opened up to keep up with ported Edelbrock heads.

 
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(Login SAE1965)
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hmmm

July 4 2006, 7:19 AM 

If I remember right the Street Master is 1970's or 80's economy manifold??? You would be better off getting a Perf. RPM, shouldn't even have to do any port work with that one. What you would save in the port work may pay for the new intake.

Scott
1969 390 Mach 1
Visit the 1969 "S" code registry at:
http://www.1969scode.com

 
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Jay Brown
(Login jaybnve)
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Surprisingly...

July 4 2006, 7:48 AM 

The Streetmaster did very well on a couple of previous intake comparisons on my dyno, outperforming the Performer RPM in HP in both a 385 HP non-CJ 428, and a 410 HP CJ engine. On the CJ, it picked up about 10 HP after a port match (which went about 2 inches into the port), and opening up the plenum per Edelbrock's original porting instructions for this intake.

Search for "Great FE Intake Comparo" (use the quotes), I think the Streetmaster and Performer RPM tests are in reports #1 and #2.

Jay Brown
1968 Shelby GT 500 Convertible, all aluminum 489" 1030 HP Supercharged FE
1969 XL Convertible, 460
1969 R code Mach 1, 706 HP 511" all aluminum FE, 10.457 @ 127.47, 2005 Drag Week Winner, Naturally Aspirated Big Block





 
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(Login werbyford)
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DId you see Jay's Comparo and the Porting Instructions?

July 4 2006, 7:23 AM 

Nick,
The Streetmaster did surprisingly well in Jay's Dyno tests.
I found it a little soggy below 2500 on a heavy car, but it really pulled above that.

A lot of Streetmaster porting posts surrounded the Intake Comparo stuff too -

And then the "new-in-the-box porting instructions" that Edelbrock denied ever existed, they are posted somewhere back several weeks ago if you search - that stuff might help if you didn't already find it = =

 
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(Login qikbbstang)
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Is there actually enough "meat" to fully open the runners

July 4 2006, 7:57 AM 

on Streetmaster FE manifolds to stock Edelbrock MR Heads?

Better yet how about moderately ported Ed MR Heads?

I presume that SOMEWHERE someone has opened the ports up and added a few layers of welded aluminum to allow hogging....

 
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Jay Brown
(Login jaybnve)
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Yes

July 4 2006, 10:31 AM 

I opened mine up to standard MR size when I did the porting job on the manifold. No problem.

Jay Brown
1968 Shelby GT 500 Convertible, all aluminum 489" 1030 HP Supercharged FE
1969 XL Convertible, 460
1969 R code Mach 1, 706 HP 511" all aluminum FE, 10.457 @ 127.47, 2005 Drag Week Winner, Naturally Aspirated Big Block





 
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(Login mystylesthebomb)
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Here are the instructions...

July 4 2006, 8:16 AM 

Howdy. Here's a text save of the instructions, original is a pdf, hit me at MyStylesTheBomb_at_Yahooo.com if you'd like the pdf that includes the pictures.

- Scott

Revised 4-11-79

INSTRUCTIONSHEET

PLEASE READ THE FOllOWING INSTRUCTIONS CAREFUllY AND
THOROUGHLY BEFORE INSTALLING YOUR NEW MANIFOLD


MODEL: STREETMASTER 390

CA TALOG NUMBER: 3205 (manifold only)

EGR SYSTEM: This manifold will not accept stock EGR (exhaust gas recirculation) equipment. EGR systems are used on some 1972 and later model vehicles and only in some states.

MANIFOLD: Most Edelbrock single 4-barrel manifolds have been designed to replace stock manifolding and will usually accept stock hardware, coolant hoses, vacuum lines, coils, chokes, etc. They normally require little, if any, alteration of factory parts as long as your stock carburetor is retained. This makes Edelbrock manifold installations among the simplest of bolt-on conversions.

CARBURETOR RECOMMENDA TIONS: See page 6 of the General Instruction Booklet for symbol nomenclature and part number breakdown.

CARBURETOR REFERENCE PARTS REQUIRED FOR INSTALLATION


REMARKS:

1. Use Cat. No. 7222, Edelbrock Intake Gasket Set.
2. Use Cat. No. 9300, Edelbrock Gasgacinch for all gasket surfaces except end seals.
3. Complete this operation before attempting installation of manifold. Install intake gaskets on heads. Set manifold down on heads and install distributor to position manifold on heads. Install push rods and rocker arms. Check all push rods of alignment to rocker arms. If push rods do not align to rocker arms, locate problem. If it is at intake manifold, grind enough clearance for proper alignment to rocker arm.
4. On some carburetor applications it may be necessary to add a 1/2" hose outlet for the PCV system. This plate (Part No.'CITE:;;9A589-C) is 112" thick and is installed between the manifold and carburetor. Check hood for proper clearance between air cleaner and hood before making this installation. If this 1/2" plate does not allow the air cleaner to clear hood, a 1/4" pipe vacuum outlet must
be used in the plenum chamber of manifold.
5. If other than stock pushrods are used, you can run into a clearance problem with the manifold; will need to grind or shim rocker arms for de-Mance.
6. For competition, modify manifold per our sheet labeled "Streetmaster 390 Plenum and Runner Modifications for Racing Applications
7. Check pipe plug in bottom of manifold for tightness.
8. Remove any dowel pins from front and rear valley gasket surface of engine block.
9. After placing manifold on gaskets and centering holes, start all manifold bolts by using four special bolts on holes by inside runners -install distributor in place for alignment -this is a must because of the close tolerance of distributor alignment.
10. Manifold will not accept stock Motorcraft spread-bore carburetor.
11. If when making this installation, you cannot use the water heated spacer block between the carburetor and manifold because of hood clearance, you must purchase approximately 2 feet of 5/8 inch heater hose from you local parts store and make a direct connection, by-passing this plate.
12. IGNITION TIMING: Edelbrock does not recommend changes in stock ignition timing. The Street-master has been designed to perform well without ignition adjustments. However, if local emissions laws permit it, you may advance initial lead by up to 20 (sometimes a slight retard from stock will help), depending upon quality of fuel, condition of engine, and method of operation.
13. CARBURETOR. CAL/BRA TION: Edelbrock does not recommend any change in stock carburetor calibration. The Streetmaster has been designed to perform well without such adjustments. However, if local emissions laws permitit, jetting or enrichment changes on the order of 0.003inch from stock jetting have shown improvements in fuel economy and performance which is a factor dependent upon fuel quality, condition of engine, and method of operation.
14. Torque all manifold bolts to 25 ft. Ibs. See Figure 1.


MODIFICATION TO THE EDELBROCK STREETMASTER 390 FOR RACE APPLICATIONS IN THE PLENUM CHAMBER: Two areas should be modified in the plenum chamber:

1. A change in vertical angle of the divider walls separating each pair of runners.
2. Removal of the "corner radius" material just above each runner pair.
By-hand grinder or milling machine, trace the opening~fthep~ur;;chani'b~r-Sothat it beco~e; square instead of diamond shaped. To view this area, look directly down into the plenum chamber (from the carburetor mounting surface). The material lying diagonally across each corner of the plenum should be removed, leaving the appearance of the plenum chamber square and not diamond shaped.

Once this material is removed, the divider walls separating each runner pair should be angled back to intersect the inside walls of the plenum chamber.

To visualize this operation, imagine a pencil placed against a divider wall before the corner material is removed. Once the plenum is made square, this leaves each of the four divider walls protruding into the plenum chamber. If you now tilted the pencil back to intersect the inside of the plenum (without changing the location of the point where the pencil contacts the plenum floor), you can see how the divider wall becomes angled off the vertical. The roof portions of each runner should also be re-radiused as they were prior to the removal of the plenum chamber corners. All four divider walls should also be re-radiused as they were prior to modifications.

IN THE MANIFOLD'S RUNNERS: The Streetmaster 390 is cast with intentionally small runners cross-sections in the area where the manifold bolts onto the cylinder heads. In fact, exit port size is comparable to the 2V 390 c.Ld. Ford truck engine. For this reason, use of the manifold on 428, SK, and other race
type cylinder heads requires enlargement in the lower areas of the manifold's runners.

Enlargement of the runners can be accomplished as follows:

Transfer cylinder head port sizes onto the manifold rather than use on intake manifold gasket (unless the gasket is exactly the size of the head ports). Using a pair of inside calipers set to the port height in the cylinder head, remove manifold material back up the runner until the calipers can be passed into the runner
to the point where runner height is greater than the dimension set on the calipers. This distance is usually about 1.5 -2.0 inches up the runner.

Now set the calipers tq the desired port width. Here you st)6Li1dexercise caution since the removal of too much material will cause you to break through the pushrod area of the manifold. If this happens, use of fiberglass or comparable patching material will provide adequate seal. IrHact, if you should break through in any areas of the manifold during modification steps, sufficient patches can be made using Edelbrock's Structural Adhesive, Metalbond, Cat. No. 9270. It would also be possible to weld up any small holes, but not if considerable heat is required since this can lead to structural distortion of the manifold.

In the course of enlarging the manifold runners, make certain that there are no abrupt changes in flow brought about by sharp edges or directional changes in the runners. Once all rough cutting is completed, finish the wall surfaces with sanding cones of about 8dgrit composition.

For modification of the manifold to be used on 428 C.I.D. FE engines, leave about a 3/16" step at the floor of the runner where the manifold bolts onto the cylinder heads. This would mean that about 3/16" of manifold material would be visible at the junction of manifold and head if you looked back up the runner
from the area of the intake valve.

Also, for race applications, the Streetmaster390 is sensitive to carburetor height. While the spacing of a carburetor affects the resonate urtft characteristics of the total intake path, you should experiment with carburetor spacers to determine optimum performance. In most cases use of a 1.0" spacer will provide the best results. This should be an open spacer instead of a 4 hole spacer.


INTAKE MANIFOLD TIGHTENING SEQUENCE
STREETMASTER 390

IMPORTANT NOTE: Installation of headers with an Edelbrock manifold may lean carburetor calibration and cause a loss of gas mileage and vehicle performance.

Installation of RV type aftermarket camshafts with an Edelbrock manifold may lean carburetor calibration and cause a loss of gas mileage and vehicle performance.

Installation of both headers and RV type aftermarket camshafts with an Edelbrock manifold may lean carburetor calibration and result in loss of gas mileage and vehicle performance.

F1gure 2. Removal of Material from Plenum and Runner Divider Walls.




 
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Nick
(Login rcodecj)
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horsepower with streetmaster

July 4 2006, 8:35 AM 

It's not sounding like the streetmaster has large enough ports to make 500 horsepower, maybe 450 at the most? How much cfm do you guys think a professional porter with a flow bench could get this manifold to flow?

 
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Jay Brown
(Login jaybnve)
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I wouldn't draw that conclusion...

July 4 2006, 10:35 AM 

Barry R has done a lot of work with the Holley Street Dominator, which is very close in size to the Streetmaster, and it seems to me he said he was making 550 to 600 HP with that manifold. Looking at the Streetmaster, I can see your concern; it was the same concern that all the rest of us had, and why we figured that this intake wouldn't work very well. We were all wrong, and it would be a mistake to count the Streetmaster out in a higher HP build.

In any case, eventually I'll have a 475-500 HP dyno mule up and running, and we'll all find out for sure...

Jay Brown
1968 Shelby GT 500 Convertible, all aluminum 489" 1030 HP Supercharged FE
1969 XL Convertible, 460
1969 R code Mach 1, 706 HP 511" all aluminum FE, 10.457 @ 127.47, 2005 Drag Week Winner, Naturally Aspirated Big Block





 
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Nick
(Login rcodecj)
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That's good to hear

July 4 2006, 2:01 PM 

A dyno test on an engine in the 450-500 hp range would be interesting. Is next week good for you? LOL

 
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(Login 67390GT)
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It's good for me LOL

July 4 2006, 3:10 PM 

As long as he puts a mr 8v on it to test

 
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(Login Barry_R)
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My Street Dominator

July 4 2006, 5:34 PM 

was pretty badly butchered up toward the end (or extensively modified depending on your point of view). I added a good bit of weld and a bunch of epoxy. I did a lot of plenum and entry/exit work, but very little in the runners themselves.

It never saw a dyno - - but you can draw some good insight from the performance. On a Edelbrock headed 452 ci engine, in a 3627 lb car, it went 10.70-10.90s at 121-123 MPH. Gonkulate that and you'll have your answer...

Barry Rabotnick
Survivalmotorsports.com

 
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(Login Bad427stang)
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There is one going on my 489 tomorrow

July 4 2006, 8:05 PM 

We'll see what those skinny ports will do

 
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Nick
(Login rcodecj)
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Can't wait to hear your results

July 4 2006, 8:20 PM 

I assume you ported it according to Edelbrock instructions or more than that?

 
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(Login Bad427stang)
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Going on bone stock for the first round

July 4 2006, 8:45 PM 

Then if it works well, going to do something else

Basically start with the Edel guidelines, but I am going to try to make the port cross section tuned for an RPM peak that meets my build and then build a fixed taper into the port from the plenum down to that port.

A little fancier but basically the same, been doing a lot of math, feeling dangerous LOL.


    
This message has been edited by Bad427stang on Jul 4, 2006 8:46 PM


 
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Nick
(Login rcodecj)
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Did you use a carb spacer?

July 4 2006, 8:18 PM 

If so what height? Any pictures? Thanks!

 
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