Well, this came in the mail the other day. I examined it and was surprised at how rough a few of the casting areas are. Could really benefit from a quick clean up with the sanding drum. There are even a few ridges on the runner mounting surface Other than that it appears quite a bit larger than stock. I haven't checked the gaskets yet to see if I need to open the ports up. I'll check later.

Question for you porters:
Should the intake ports from the runners be smooth and the exit ports to the heads be rough, or smooth all the way through?

Matthew

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If what I have read is correct, if it's air only, a smooth surface is best. Air fuel mix should be an 80 grit surface.

Thanks, Joe.

One more thing now that I looked at yours - check out the hole next to the ports (this is Joe's TPIs intake) it is a perfect circle, compared to my ragged casting. Comments?

I've owned two Accel and one TPIS bases, from what I can see, your intake looks quite normal. Edelbrock's deburring processes are also just as lacking as I've seen on the others. It's not uncommon for your intake to look as it does. But I'm sure I'm not alone in thinking they should be
done with a bit more care considering what these things cost. I'm not sure what kind of runners you're gonna use, but if they're SLP, Edelbrock, or other CAST runners, I'd look into Extrude-honing for them. Mostly because I'm impatient as he!!. Also because of the finished product.
I'm pretty sure others will disagree with me, and that's OK, but that's what I'd do.

smooth vs. rough cast won't make a lick of difference really.

What you're more concerned about is shape. You want to clean up the transition from those ports.

Edelbrock has a big crosssection, but the entry ports are undersized, so that it fits the stock runners. I assume you're upgrading the runners too, so you need to port all that out.

It can be transitioned from stock runners, but it's not ideal. I have that on a setup on mine.

Basically if the diameter increases suddenly at too much of an angle, the airstream seperates from the wall and creates a ton of turbulence, like the wake on a boat.

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I already have SLPs in the garage ready to go on. I was planning on siamesing them an extra inch or two, first.

Are you going to port match all the parts?

If so, those flashings on the end won't matter since they're just going to be ground off anyways.

Well, let's just say looks can be deceiving! I measured the intake ports on the new intake and they are actually smaller than the stock manifold! But the interior area seems like there is much more volume inside. So I guess I've got some work to do.

Matthew

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That's odd. Are they sized to Edelbrock runners?
Maybe they figure you will be grinding to match your setup so they just leave them small?

FYI - Edelbrock developed the "endura-shine" finish to give them a chrome look without the work. They don't have to polish the surface first; it's a heavy powder coat!

Damn! That somabeach looks like they drop-kicked it out the door! I'd probably be tempted to send them pics and ask if they think that's an acceptable specimen -- especially if it's one you're posting for others to see on the NET! LOL (Who know's,,,maybe they'd do an exchange and pay for shipping both ways.)

As far as porting, I agree you shouldn't need to do much thru the tubes. (FWIW, I believe exhaust ports and non-fuel mixed intake ports are supposed to be smooth, but the intake runner ports in your heads can be rougher to help tumble/mix air/fuel). So, you could go thru the runners and smooth out the bumps if you want (like I did).

Here's a pic of mine. I took out all the taper (into the base) to maximize flow thru it, matched the bottom of the SLP's to that, matches the base to the heads, and siamesed/smoothed the interior of all runners.



Edit: The way I opened up the base runner (mouths) is most noticable in the two runner holes on the right (of the base).

And,,,If you're not SICK of grinding and sanding by the time you're done, try polishing the whole thing just for fun! LOL

Thanks for the pics, Gregg. I don't think I'll go quite that extreme, but it's nice work and I know you put a lot of hours into it.

Matthew

Gregg - that looks sweet! I bet it flows like a motha, too!

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Yowzahhh - I hope drool doesn't stain that!

That really is pretty incredible!

OK something isn't right here. I need some help. Does anyone have a verified stock intake manifold laying around that they can measure???

Here's the deal: the GM manifold I have on the shelf I purchased over a year ago. It was sold as stock with no porting. I never gave it a second thought. Now looking at it closer, it appears it may have been ported. And if so the person did a nice job. The runner inlets are very round, and very smooth compared to the casting farther inside. Plus, the diameter is larger than my new edelbrock. That can't be - can it???? Check it out:

GM Manifold:



versus Edelbrock:



versus SLP runners:



Now take a look at the intake ports on the GM manifold - they are smooth:





So am I imagining things here, or is this GM manifold already ported??? If so, the edelbrock is going on ebay.

Matthew

If anything that GM OEM intake was port matched. That is not porting.

The Edelbrock intake has a shit load more meat on it. Remember as stated above, they ship it with stock port size so it will work with the stock runners. You need to bore it out to get the greater performance potential out of it.

This is a case of cut once... you can never make these things smaller again.

I agree with the post above, extrude hone that Edelbrock part, clean up the flashing and be done. It will flow a ton better than OEM ever will.

This is the pain with aftermarket performance at times - it requires attention that OEM won't. It's just the price we pay for the added performance.

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Unfortunately, extrude hone on that intake would be, I dunno, $400 or so. Way too expensive. Add the runners in for about another $200-250 and that's a buttload of money.

http://www.gethoned.com/price_list.php?get_price=automotive

http://www.rlengines.com/Web_Pages/extrudehoneprice.html

http://www.boneheadperformance.com/Me ... chant.mvc?Screen=EH_PRICE

they charge out the ass for that, don't they? I didn't realize it was so damned expensive. I don't get it, either... hook up, walk away.

Geez...

You're looking at all the same things I did (honing, how much to port, whether to reuse base, etc...). I decided honing was too pricey for the base -- though I considered the runners (cheaper). Then I decided to sit down first, and see what I could do "manually". One thing led to another and I got jiggy with it.

Your stock base is DEFINITELY ported -- as stock size is a bit smaller than 1.5" (about 1.47"). You can get that Edelbrock out to 1.7" - 1.75". And, it's a bit bigger throughout the tubes (than a stock unit). As mentioned above, the Edelbrock has a pronounced "lip" at the opening in order for it to match the stock runners. (That's stupid IMO, since having a larger base opening it's going to hurt.) Remove that lip and it's a bit bigger than stock.

Depending on your performance goals, you might considering using that stock base -- though you'll likely lose 5-10HP (esp up top). The difference won't be huge though. Can you return the base (if you don't want it)? I have to wonder how much you'll lose due to the casting flaws.

Note: If you haven't seen it, google "Ten Times the Torque". You'll find a TPI Shootout of 8-10 intakes. Notice one combo used an extrude honed stock intake where another Edelbrock only made a few more ponies. Since that's on a 383, I think there's a parallel you'll see with a stock Edelbrock vs a stock GM base. (By that I mean stock throughout the tubes. And, that both are ported with equal sized openings.)

Finally, if you want to smooth/enlarge throughout the tubes, all you need is a fast drill, drill-bit extension, and 60-grit flapwheels in 1.5" diameter. You might be surprised at how fast you can pile up aluminum dust. Finish with 120-grit -- and WEAR A MASK if you do it.

You can use the flap wheels to port the openings as well. If things go to slow, look at buying a carbide burr in a sprial cone shape. They make them with 4" long shanks if you really want to get inside something. FWIW, high-speed drills are about right for this type of grinding since high-speed air equipment can cause burrs to get balled up with alum.

Gasket match your Edel. base inlet to whatever size your SLP runners end up and gasket match the Edelbrock base oulet to your heads. That way your're reaping the benefit of the larger volume base without going hog wild on porting.

Yeah your stock manifold is ported. The edelbrock matches the stock gaskets and runners.

(where do you even get larger gaskets?)

FWIW, I did not do any siamesing on the 5 & 7 intake ports. Those ones steal enough air from each other as is, so I want them run separately all the way to the plenum.

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Thing is, the stock mani is already gasket matched/mild ported to the SLPs - check out the dimensions. I understand about the additional flow in the base, but the difference may be negligible in this case. I don't know how much time I want to spend porting a brand new product

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My SLP runners came with gaskets. Interesting on the 5/7 ports...

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Use these to make it easy. Port-match to these and you'll be "in like Flint".
http://www.summitracing.com/parts/MRG-146/

For what it is worth, many years ago, I talked to Lingenfelter Performance about porting the base and they told me if using the Accel long tube runners, porting the Accel base intake wouldn't be much of a benefit, but if I was using the Superram, I could expect to see 15 HP or so....

But, naturally, I didn't listen to them..... I was running the Accel long tube runners at the time and I went ahead and ported the Accel base and did a bunch of before and after track tests..... I didn't really get a significant performance improvement... it showed right around 1-2 hundredths on my bracket car..... which was probably 2-3 HP or thereabouts.

I think you might get a benefit from porting that intake if you spin your motor north of 5000 rpm.... which you're probably not going to do with those tubes you're putting on it.

Just food for thought.

good luck !

Thanks BB. I'm leaning towards using the GM ported base at this point. I'd like a superram in the future, but the right deal hasn't come along yet.

Matthew