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Should I port my Edelbrock heads?
I have my 474 apart installing a xr288 comp roller cam. I have a 474 Butler rotating assembly. My heads are the 87 cc Edelbrocks that have been port matched.
I wanted to do a valve job while I have the heads off. The shop close to me is Mid America Racing engines and they are pretty good. I'm taking the heads there for the valve job. They have a flow bench and build some pretty stout motors so no doubt they can handle the job. My heads are EO-D-215-49 1.5 rockers XR288HR cam Edelbrock performer dual plane 850 Holley Dougs Headers Will it be worth it to have my heads flowed and ported? What kind of gains could I see if any with my set up? |
what does it run now? goals? fuel? cost? vs what else?
But likely yes it would help |
If you rev the engine over 5000 rpm it will help to get the heads ported. A port match and mild bowl clean up will get you to 310 cfm @ 28" H2O. It depends on your intake and the rest of the system but if you're spinning into the 6500 rpm range you can take all you can get flow and area wise.
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I've never had it to the track and probably won't. I want to run pump gas and basically keep it on the street.
Not sure what they charge to port heads? I'm going to go up to his shop in a week or two when I get back from vacation. Not sure what these heads flow stock vs fully ported? I'm sure it will help make more power just not sure how much? |
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I'm just running an Edelbrock performer dual plane. I have a 78 T/A so that's the best I can do and run a shaker. |
The intake will be a limiting factor and will limit the improvement with porting your heads. Unless you change the intake, I personally wouldn't go after porting.
I run a torker2 intake on my TA with the shaker and it works fine. The torker2 it a much better intake for your heads than what you have. It will work well with ported heads too if match it to the head and make sure you're port area at the plenum is at least as large as the head/manifold interface. I can send you info on intake heights for the shaker application if you'd like. The bottom line is stock, performer or torker2 is all that will work without major mods. The torker2 is the only one that will make much power IMO without major work. Good luck with your build! |
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That Perfomer intake is a big ckoke point. A stock intake is better than the Perfomer by far. Search Cliff Ruggles about intakes. He did extensive testing on intakes in your power range.
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You sure you don't have the Performer RPM? That would make a lot more sense and fall into place with the rest of your combination.
Since you are doing the heads over, I'd be more inclined to set them up for 1.65 rockers. Sell your 1.5's and you won't be in to the new rockers for much. Porting is expensive, and the RPM range you are in doesn't justify the money. One of my street combo's was a 440 (65 over 428) with the 85cc Edelbrock heads, 1.65 HS rockers, XR288HR cam, 3" exhaust, and an Offy 2-4 manifold. Horsepower peak was 5,200 RPM because of the intake manifold. Plenty of CFM with two 600's, but just not that efficient of manifold. An RPM would have worked much better - just not looked as cool. |
buy a polished tomahawk rebop, sell the eekebrock for about the same price as having it powdercoated, and reap the power benefits for free.
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I would not touch a thing with those heads for your use,and be sure to NOT gasket match the exh, leave them at the as cast size!
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Aaron I think the flow bench was a little generous if they went 310 with just soome clean up. The heads I just sent to Dave at SD had a port 2.3 tall otherwise a 1233 gasket some pocket work also and only went 290 @ .700. Guy I got them from had them cleaned up by a machine shop. Weird deal was the springs they used were only 100 seat pressure at the 1.760 IH they used.
Still a clean up and matching will pick you up a bunch more over some iron heads unless thye have really think walls. I do agree an RPM or T2 are really needed a factory intake even ported will probably be a cork. |
CNC port and valve job 1250$ Allpontiac Tiger Cub CNC program 345-355cfms,parts extra.Bill C.
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The Performer RPM changes the equation. That manifold will work well with what you have and you would benefit from porting the heads.
I'm not sure how you packaged the RPM under the shaker. I took my RPM off because I couldn't get enough clearance and run a big enough air filter with shaker. Quote:
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Skip,
You might be right. I'm running on memory here but I think the heads peaked out at 290ish on the bench. The 310 cfm had some clean up, light blow work (mostly around the valve seat) and a little SSR work. I don't remeber if they had any work at the flange completed or not. The mid 90's were a long time ago. :) Thanks, Aaron Quote:
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The mid 90's were a long time ago.
Amen Brother:) |
What about the northwind? seem to recall seeing some good dyno results, maybe on sd's site?
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Yes...you should port your heads! These things (Pontiacs) always need more air moving through them . Your head otb is about 290 ish??? in intake cfm . Can gain about 40 cfm in the induction tract. Depending on the manifold , carb and camshaft...that COULD be about 80-100 h.p.! It is very dependent on the total package though...I'd think single plane automatically but...the Performer RPM is pretty good even still. Good luck with your project ! Some pics of our CNC'd Eddy RPM here . Cheers , Johnny
http://i1217.photobucket.com/albums/...dyPerfRPM1.jpg http://i1217.photobucket.com/albums/...cture002-1.jpg http://i1217.photobucket.com/albums/...Picture004.jpg |
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