Hey guys, i've read on here you can gain a easy up to 10 h.p. by cutting down the divider in a edelbrock performer intake. anyone have a pic or can tell me how far down etc to do that? thanks

 

You might want to ask yourself, if it's that easy to gain 10HP, why didn't E-brock make them that way?

The reality is that this is a trade-off, and how much you gain (if anything) depends on the complete motor combo and intended RPM range. Cutting the divider turns a dual plane intake into a single plane. You are trading low RPM torque and HP for higher RPM HP. If that is consistent with how you plan to use the motor, fine. If your car is primarily street driven and you care more about getting away from a stoplight, you may not find this an improvement.

 

Hmmm sorry Joe but I have to disagree.
There are some intakes that are cast with a notch in the divider, do a search and you'll see.
And it's more like 5-7hp on avg. And it doesn't typically hurt power below the previous peak, only adds above it.


Thanks.

 

any ideas on where to notch and how far down?

 

djdaveofkc have a look at this video. manifold comparo with dyno and your notch, exactly what your talking about.
If you don't want to watch the whole thing, go to about the 6:00 mark.
Its a good vid anyway and doesn't go for long.

 

I have an Edelbrock Performer intake on my 455 and it's a great manifold. I suppose you may be able to gain a little bit of HP with this mod, but like Joe said you have to ask yourself what the car is going to be used for. If you are seriously considering this mod then you should also be plugging your exhaust cross over, porting and polishing the heads, filling the center divider on the exhaust ports, etc.

I have heard that this divider in the intake causes problems for aftermarket EFI systems. I guess you don't have to eliminate it though. Just milling it down a bit or adding a spacer seems to make the EFI systems happy.

 

Sorry but I disagree with most of your statement.
You're assuming that all of the mods you mention are directly related, they're not really.
I can tell you from first hand experience, even a mild build will benefit from intake mods WITHOUT any or all of the other things you mentioned.

 

The notch in the original Edelbrock intakes was for the three barrel Holley of that era. It had nothing to do with being a single/dual plane hybrid.
The large oval secondary throttle blade would contact the divider if the notch wasn't present. Some other brands of carbs elected to notch the throttle blade itself or make it in the shape of a pair of sunglasses to clear the divider. Of course QJets don't have this problem as they use two separate blades as do most carbs.

 

If one wants to build a 455 and squeeze all the HP they can out of it surely they would do all of these mods and more. Then again, if you want a 455 with maximum HP there are better intakes out there that wouldn't need modification.

That's intersting to know. Thanks for the info.

 

I want to clarify one thing. The notch I'm referring to is the small notch that was common back in the day around the same time that the 3 barrel Holley was available. I haven't seen them notched like that in decades. Nowadays the newer manifolds have a much larger notch that extends a greater distance on the divider. That I'm sure is a way to get the best of both worlds (Single plane/Dual plane) from the intake.
The Edelbrock/Carter new model Thermoquad now uses a goggle valve to clear the divider similar to the 'sunglasses' one I was talking about in the previous post.

 

We can all go back and forth about this, but maybe this will help.
Just give Keith Wilson a call at Wilson manifolds in Ft Laud Fl. He knows a thing or two about intakes. I'm confident he can give you what you'll need to verify this one way or another.

 

I'm not an expert by any means but I read by cutting down the divider you loose the strong signal to the carb created by the dual plane effect, even using the wrong carb gasket can ruin the effect. Factory Olds intakes are purposely divided for this reason. The "Trick of the Week" will probably hurt low end response, as Joe said. The factory engineers had extensive test equipment at their disposal, I'm sure they would've notched the divider if it was worth something. Before ruining the intake, experiment with spacers first you'll get the same effect. Good luck with your project.

 

Interesting video. Thanks. I've read on this forum about the notch so that's why i was inquiring about it.