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Carb Swap Questions: Edelbrock to Summit

4379 Views 97 Replies 22 Participants Last post by  swooshdave
When going from an Edelbrock 1406 to a Summit 600 will the Summit bolt right on? Are the bolt patterns and such all the same? Hoping to place one order and not several. Thanks!

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Not in the boosters & venturii, no. That said, turbulence is a deeeep rabbit hole 馃槈
When I reload black powder cartridges like 50-70 and 50-100, I drop the powder into the cases through a 32-inch long tube. The tube has 5 or 6 sheet metal screws that go through it creating "baffles". The baffles cause the powder to "flutter" in and settle more compactly. The settling greatly improves burn consistency...

Probably apples and oranges...
Color me stupid: wouldn't rough areas increase turbulence and improve mixture?
Sometimes yes sometimes no. In this case no because it has to meter and evenly disperse the fuel going into the airstream.
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When I reload black powder cartridges like 50-70 and 50-100, I drop the powder into the cases through a 32-inch long tube. The tube has 5 or 6 sheet metal screws that go through it creating "baffles". The baffles cause the powder to "flutter" in and settle more compactly. The settling greatly improves burn consistency...

Probably apples and oranges...
Interesting. I know some black powder guys, I鈥檒l ask if they do the same/similar. Mostly 45-70, a few guys shooting 45-90
There are a bunch of BPCR (Black Powder Cartridge Rifle) shooters between Prescott and Tucson. Most shoot 45-70 or the die-hard competitors, the 45-90. Advantage to the 45-70 is the ability to buy ammo off the shelf and reselling a 45-70 is infinitely easier than a 45-90.

Most shooters load using a drop tube, the baffeling is my wrinkle, at first I drilled small holes and used thin wire. Later I went to sheet metal screws to create a larger disruption to the powder charge as it dropped down the tube. The improvement in settling is measurable with a vernier calipher.
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Did you get it it to idle down? What did you find?
No, in the winter I'm not as motivated to go out to the cold garage.
Slight update (weather has been improving). As I mentioned the carb spacer/gasket provided with the carb was pathetic at best. Probably best described as cardboard with dried tar. And not high quality cardboard. I suspected so air was actually sneaking in through the cardboard and that the recommended torque for the carb was too low for the spacer. So I cranked it down to "hand tight".

Now with the throttle screw backed off I'm getting it to idle in the 720-750 range when hot. I'm still not happy with that but at least it's drivable.

It will not run correctly with the PCV hose attached. So it's just laying there (for now) and the carb port is plugged up.

I'm thinking of taking the carb back off and trying a more traditional spacer/gasket. That will at least eliminate the cardboard as a suspect.
I found that gasket strange, too, and really cranked down on it (relatively speaking) to make it seal. I think your idea is better: putting in a real gasket.
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I've got it to reliably idle around 700-750. I think that's a lot higher than what most people try to achieve with a manual trans. This is with the idle screw not engaged. And no PCV hose attached to carb.

I sprayed carb cleaner around the base of the carb with no apparent change in idle.

I've always suspected poor fitting butterflies as the actual cause of my issues. I'm going to yank the carb again at some point and show you what I mean.
Ok, on a side note...I have a few of the summit carbs, and have been finagling with a 600 the last few days. The thick gasket is required by Summit as the pump diaphragm cover is lower than the base gasket and can cause interference with the carb not to sitting flat against the manifold. This thick gasket is also fully open...which nullifies the ability of a DUAL PLANE manifold to pull mixture into one bank or the other. In other words, the thick gasket makes your dual plane a single plane...as the mixture bleeds over the dividing wall of the intake. I have not remedied this situation. I plan to get a phenolic 4 hole spacer to put between manifold and carb to eliminate the thick gasket. I currently have a 1" open spacer between manifold and carb, thereby increasing the bleed over from the dual plane intake. I did have to make float adjustments, but other than that, they generally run pretty damn good out of the box.The car still runs great with the incorrect spacers. I have a decent idle, and the curb idle is very sensitive. My choke is wire open, but may play with that some more. It is getting warm here, so no need for a choke really...
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I tried to post that^ on a social media platform (that shall remain nameless for now). I got put in the doghouse for 鈥榠nciting violence鈥 馃ぃ what a croc of sh*t, some people are wound far too tight 馃ぃ
I tried to post that^ on a social media platform (that shall remain nameless for now). I got put in the doghouse for 鈥榠nciting violence鈥 馃ぃ what a croc of sh*t, some people are wound far too tight 馃ぃ
Thank God you didn't mentioned your favorite oil cuz that will get you permanently banned.
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This thick gasket is also fully open...which nullifies the ability of a DUAL PLANE manifold to pull mixture into one bank or the other
Ummm, no.

Air, like any other element, has mass. Having mass, Newton's Laws apply and what is coming straight down the throttle bores will want to continue in the same direction. Yes, there will be some boundary-layer air when it reaches the area of the plenum divider that may become turbulent and spill over but the vast majority will keep going in its original direction. FWIW, you'll note many dual-plane intakes actually have a "notch" in the divider to encourage this...

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Ummm, no.

Air, like any other element, has mass. Having mass, Newton's Laws apply and what is coming straight down the throttle bores will want to continue in the same direction. Yes, there will be some boundary-layer air when it reaches the area of the plenum divider that may become turbulent and spill over but the vast majority will keep going in its original direction. FWIW, you'll note many dual-plane intakes actually have a "notch" in the divider to encourage this...

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Yep, as I recall the Performer RPM does not have a notch but the RPM Air Gap does. My understanding is that it helps balance the signal for EFI.
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Dave, did you check the secondary butterfly stop screw like I said in post #78? Maybe it's the camera angle but in the photo in your post #27 it looks as though the screw is a bit too far in. You need to remove the carb to access this screw & use a good quality screwdriver. The hole for the screw is peened to prevent the screw from vibrating out. Maybe this will bring your idle down to where you're happy with it.
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Ummm, no.

Air, like any other element, has mass. Having mass, Newton's Laws apply and what is coming straight down the throttle bores will want to continue in the same direction. Yes, there will be some boundary-layer air when it reaches the area of the plenum divider that may become turbulent and spill over but the vast majority will keep going in its original direction. FWIW, you'll note many dual-plane intakes actually have a "notch" in the divider to encourage this...
Good to know. Now I won鈥檛 worry about it on the middle of the night.
Dave, did you check the secondary butterfly stop screw like I said in post #78? Maybe it's the camera angle but in the photo in your post #27 it looks as though the screw is a bit too far in. You need to remove the carb to access this screw & use a good quality screwdriver. The hole for the screw is peened to prevent the screw from vibrating out. Maybe this will bring your idle down to where you're happy with it.
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I did not. I will when I take the carb off.

I like your signature. For some of us it's "We do it right because we do it twice!"...
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I did not. I will when I take the carb off.

I like your signature. For some of us it's "We do it right because we do it twice!"...
Have you had a chance to make any more progress in the carb?
Have you had a chance to make any more progress in the carb?
It was actual nice enough to drive it. It鈥檚 ok. But I haven鈥檛 been able to make any changes.
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