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Edelbrock 600 cfm carb swap

2K views 18 replies 6 participants last post by  75gmck25 
#1 ·
Hello everyone. I've got a bit of an issue with my new carb. I swapped my tired old one out for a shiny new one, its an edelbrock 1406 600 cfm. Its going on a 79 K10, SWB, 350. I'm pretty much set to do the install, just need to run power to the choke and install the new fuel line. My question is about the throttle bracket. I'm mostly a newb at this stuff, and I'm not quite sure what I need to mate up the old with the new. Any help would be greatly appreciated. Please see pics. Thanks in advance for any help, and I'll provide as much information as I can.

(Sorry for the crooked pics)
 

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#7 · (Edited)
#8 ·
Excellent info, thanks for the help. I'm wondering whats the worse thing that could happen if I don't put a fuel regulator in. Not to excited about the extra plumbing, and I'm not going to be layin big rubber with the truck. Not with the np203 transfer case for sure, lol! So is it really required?
 
#9 ·
I think there are a couple things that make the Edelbrock a little cranky one is fuel pressure, it's not happy which as much as the Q-Jet or Holley puts up with hence a regulator even with a mechanical pump. As long as the pump is a stock replacement the regulator can be a simple non-bypass type which won't get you into any additional plumbing from the sense of a bypass type which requires a return line to either the tank or ahead of the pump.


The other thing it likes is to be cool so they function better with some insulation between the carb and intake. I have yet to find an insulating adapter for the Q-Jet spread-bore intake to a square-bore carb. If you can do some work with fabrication tools like a saber saw, drill running a hole saw, and a hand or rotary file you could carve your own adapter from a piece of 1/2 to 3/4 inch thick phenolic which would go a long way toward keeping the hot intake from cooking the fuel bowls dry after shut down.


Bogie
 
#11 ·
At the minimum, use one of these between carb and adapter.

https://www.summitracing.com/parts/edl-9266

Or one that's thicker if possible. A major problem is the fuel percolates on hot days after you shut off a hot engine. And then 30 minutes later, you have to crank the starter for 5-10 seconds to fill up the float bowls. Pretty embarrassing at a car show or drive-in.:(

On another note, I've used lots of 1400-series carbs, typically with AC/Delco pumps, but never with a regulator. But if already have one, that's great. Edelbrock's website says optimal pressure is 5.5 psi; max is 6.5 or 6.0 psi, depending on which paragraph you read.:confused:
 
#14 ·
Thanks, we need the heat!

So I'm doing a bit of pre install work, so things can roll right along when I get parts. I'm hooking up the power for the electric choke, and looking for a good source. Keyed 12V according to the instructions. So......the old quadrajet that came off had an automatic choke, which was wired into an automatic choke relay, not even close to original, and not a great job was done. I just want to clarify that I no longer need that relay, and can removed it, using the power wire to go to my new choke. Thanks again for any help. Here's exactly what edelbrock says for the install, and also a pic of the rats nest. Cheers.

"The Electric choke on our Performer Series and AVS carburetors needs to be hooked to a "keyed" (while the key is in the on position) 12-volt power source, with a good ground. Verify there is no voltage when the key is in the off position. Do not connect the positive wire to the Ignition Coil, ballast resistor or Alternator."
 

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#16 ·
Edelbrock sells several models of throttle brackets. I think I used the 8032 bracket, which has fittings for throttle, TH350 kickdown, and cruise control.

I would have to look up the wire color, but your truck should have a key-on wire that comes out of the fuse block into the engine compartment. In trucks with dual batteries it is used to power a relay that disconnects the secondary battery (used for campers) when the ignition is turned off.

Bruce
 
#17 ·
Thanks Bruce,

I got all excited today, plumbed the lines and regulator, routed the electrical, but wasn't able to use the original bracket. I've got some metal work friends at work, so I'll see if I can mod the one I have, but if its a no go, then I'll try out the edelbrock bracket.

On a good note, I went ahead and bolted the carb down, and everything is hooked up minus the throttle, and was able to spark it up! Fired right up and ran like a top! The electric choke ran like a dream, hooked up to keyed power. Pretty pumped to finish up and get her back on the road as soon as the salt is off the roads!

Thanks everyone for all the help! Cheers.

Steve
 
#18 · (Edited)
The Edelbrock brackets are convenient because they are made in two pieces bolted together with elongated holes. It lets you adjust the part that holds the cable, front to back and up and down to get it aligned with your cables.

You will find that your stock air cleaner does not clear the electric choke and fit down on the Edelbrock unless you use a short spacer like the #8092. I tried both an aftermarket Edelbrock air cleaner (I used a 14", either the #1221 or #1224, which flow well), and a 1" spacer with the stock air cleaner. Using the Edelbrock air cleaner was easier because the plastic spacer tends to flex/slip in the wrong direction when you are installing the stock air cleaner.

Even some of the Edelbrock air cleaners, like the #1207, will not work without a spacer, and I think that is a model you find in many parts stores. Make sure you buy one that Edelbrock says will clear the electric choke.

I never used a pressure regulator, but I did check fuel pressure with an inexpensive gauge to make sure it was not too high.

Bruce
 
#19 ·
When you get your carb running you may find that it has the rather infamous Edelbrock "bog" when you try to accelerate briskly. First make sure that idle is set correctly, and use Edelbrock's procedure to verify how the truck runs in cruise and power modes. Then go after the bog, which is usually caused by a too slow transition from the cruise section of the rods (lean) to the power section of the rods (richer).

In many cases you cannot cure a lean part throttle bog with more accelerator pump shot, although it seems everyone tries that first because it works on other carbs. The real fix is to buy a set of Edelbrock step-up springs (part #1464) and swap in a higher rated spring. The stock step-up springs are rated at 5", which means they transition the carb to power mode when vacuum drops to 5". If you buy a spring kit you will get springs for 3,4,5,7,and 8" . They can be swapped easily from the top of the carb, and you will probably cure the bog by moving to a 7" spring, or maybe even an 8". The higher rated spring will "step up" to power mode earlier and fill in that bog.

Bruce
 
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