Call me stubborn (cheap), but I have a hard time believing that an aftermarket intake will make a drastic difference over stock, assuming the stock intake can be ported to match the runners. I'm getting ready to switch to a Super Ram (just purchased) and I think I can open the intake bores to match the SR runners. The intake is already ported & gasket matched, but I was going to port it more to match the SR runners in order to go ahead and make the switch. I plan to upgrade heads (& intake?)later. If you think there is a worthwhile difference, please tell me what the difference is. Thanks, and sorry for a long post.

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87 GTA, auto w/2075 stall, 3.27 rear, L98 .020 over,Comp 269HR cam & 1.5 roller tips, ported heads w/3 angle vj & brnz guides, 52mm TB & airfoil, SLP runners, ported plenum, ported intake, Edelbrock TES, AFPR, MSD 6A/Blaster coil, MAF screens, cold-air induction, vortec muffler, heated O2, Ed Wright Fastchip.

 

You can port the stock intake manifold to match what you get with an out-of-the-box aftermarket intake manifold. You can then port that even further to flow more. So the aftermarket intake is better, but it needs porting and port-matching.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
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If I can open the stock intake bores to match the diameter of the SR runner exits, what benefit is there to opening an aftermarket intake any larger?

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87 GTA, auto w/2075 stall, 3.27 rear, L98 .020 over,Comp 269HR cam & 1.5 roller tips, ported heads w/3 angle vj & brnz guides, 52mm TB & airfoil, SLP runners, ported plenum, ported intake, Edelbrock TES, AFPR, MSD 6A/Blaster coil, MAF screens, cold-air induction, vortec muffler, heated O2, Ed Wright Fastchip.

 

Well, after putting a hole (DOH!)in my manifold porting it to match my TFS heads, I doubt that you can really port it to the extent neccessary for the SR. You can probably clean it up and port match it, but you can't straighten out the short-side radius at the heads. I'll have pictures posted once I get mine fixed.

I have to add that I do expect my combination of ported plenum, siamesed SLP runners and ported manifold to run up to 6000RPM with the LT4 hot cam. I'll post those results if it ever gets finished.

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Bob '89 Formula CC350
Last(lost)Member of the Elusive Great Lakes Crew
My car's homepage

[This message has been edited by RCR (edited January 11, 2001).]

 

You can port-match the stock intake to match the ports on the heads, and the runners, but the internal area is smaller. In other words, the stock intake necks down inside, while the aftermarket intake stays the same. Make sense?

 

I've ported the bores of my intake to a consistent diameter, then blended that into the rectangular opening at the head, & port matched at the head. Assuming it's possible to achieve a consistent diameter thru these bores as large in diameter as the SR runners' exits, is there still some benefit from the aftermarket intake? For instance, is the intake runner bore itself different in shape to allow improved flow? An example: after porting a stock head, there isn't a lot of difference by visual comparison to an aftermarket head, but the shape of the runner allows the aftermarket head to make higher flow numbers. I'd rather avoid the $300+ cost of an aftermarket base intake, unless I ruin mine trying to max port it!

RCR, I fully opened the siamese area in my SLP's to about 3" deep (as far as the tool would reach), and siamesed the plenum exit holes to match - theorizing that I was extending the plenum volume & shortening the runner length by doing this, which might emulate the de-tuned systems (SR/MR). My cam is a Comp HR269, which is similar to the Hot cam (218/224), but more aggressive ramps. The siamesing helped on top end, but the motor still seems to run out of air and power decreases as it winds past ~4800 rpm's - it will reach 6000, but it takes longer to wind the last 1000 rpm's than up to 5000. It's likely the junk stock heads are the restriction at this point. I advise removing as much of the runner divider wall as you can in order to move the usable power band higher. No loss of torque noted. E-mail if interested and I'll send some pic's showing what I did.

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87 GTA, auto w/2075 stall, 3.27 rear, L98 .020 over,Comp 269HR cam & 1.5 roller tips, ported heads w/3 angle vj & brnz guides, 52mm TB & airfoil, SLP runners, ported plenum, ported intake, Edelbrock TES, AFPR, MSD 6A/Blaster coil, MAF screens, cold-air induction, vortec muffler, heated O2, Ed Wright Fastchip.

 

Well I had a self ported stock intake on my ZZ4, ported as far as I could safely go I felt. I then swapped it for an Edelbrock Hi-Flow, also ported by me. No numbers to back it up but I felt a good difference. The port design on the Edelbrock is different they way it flows thru the intake compared to the stock intake. I can see daylight much better end-to-end thru the Edelbrock then the stock intake. Believe what you want. I wouldn't go back.

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Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
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BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

I agree.. the runners are not only larger but reshaped to increase velosity/flow. John Lingenfelter says a ported stock base will not flow as well as a stock SuperRam base.

The Accel base is already a good match to the SuperRam runners and a small race port felpro intake Gasket. You have already spent the money on the SuperRam. I would save for the Accel base If I was you.

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

Thanks for the input guys.

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87 GTA, auto w/2075 stall, 3.27 rear, L98 .020 over,Comp 269HR cam & 1.5 roller tips, ported heads w/3 angle vj & brnz guides, 52mm TB & airfoil, SLP runners, ported plenum, ported intake, Edelbrock TES, AFPR, MSD 6A/Blaster coil, MAF screens, cold-air induction, vortec muffler, heated O2, Ed Wright Fastchip.