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Hi all - just had my L46 motor rebuilt for my 1970. In the course of the rebuild, I am switching from the Edelbrock Torker intake manifold to the Edelbrock Performer 2101. I am also switching from the Holley DP carb that was on it to the original Q-jet (rebuilt by Lars!). Since I now have a new carb and intake, I think I need some help on where the various vacuum lines should be connecting to. Does anyone have a good picture or diagram that I could follow?
Which vacuum lines, I believe you only could have, distributor vacuum, power brake, and HVAC , doubt you still have an air pump.
The diagram in the post above shows you the stock distributor source.
So exactly which one do you need help with?
I believe I had three lines with the old set-up. I do not have power brakes. Here is the first one I had (labeled with blue tape "1"). I connected to the front of the carb, at the very bottom. I believe this then went to the distributor? Where will this connection be on my new setup?
Here are two others...one is marked with blue tape "2", and it goes into the intake manifold. There is another connection, not labeled, that goes just above that into the bottom of the carb. These are on the back end of the carb. I believe the line labeled "2" then went to the vacuum filter and check valve and then to a "y" connector etc. Where will this connection be on my new setup with Performer intake and Q-jet?
I am aware of only three intake/vacuum connections that need to be fitted around your carb. Two of them have to do with the fuel vapor collection canister. The larger PURGE hose coming from a "T" connector at the PCV valve in the left valve cover. That line should connect to a large fitting in the front of the carb throttle plate. That is where the vented fuel vapors get sent back into the fuel/air charge. There should also be a smaller vacuum line which connects to a 'timed/ported' fitting on the carburetor. This is the 'signal' line going to the vacuum switch on top of that fuel vapor canister. I believe that the fitting on the front-left of the Q-jet is a "timed/ported" fitting. The third vacuum line is the one coming from the vacuum advance can on the distributor. That should be connected to the long-tube fitting on the right side of the carb, surrounded by the choke mechanism/linkage.
Hi all - just had my L46 motor rebuilt for my 1970. In the course of the rebuild, I am switching from the Edelbrock Torker intake manifold to the Edelbrock Performer 2101. I am also switching from the Holley DP carb that was on it to the original Q-jet (rebuilt by Lars!). Since I now have a new carb and intake, I think I need some help on where the various vacuum lines should be connecting to. Does anyone have a good picture or diagram that I could follow?
What hoses you needs depends on which 70 L46 carb you have. 7040507 (California version) or 7040207 49 state version. 7040207 version
I believe I had three lines with the old set-up. I do not have power brakes. Here is the first one I had (labeled with blue tape "1"). I connected to the front of the carb, at the very bottom. I believe this then went to the distributor? Where will this connection be on my new setup?
Here are two others...one is marked with blue tape "2", and it goes into the intake manifold. There is another connection, not labeled, that goes just above that into the bottom of the carb. These are on the back end of the carb. I believe the line labeled "2" then went to the vacuum filter and check valve and then to a "y" connector etc. Where will this connection be on my new setup with Performer intake and Q-jet?
Your distributor connection is in the Dr Rebuild document that was posted above.
Did you look at your Quadrajet in the back?
Do you see a multi-port vacuum fitting that the rest of your hoses connect to?
Did you look at the 2101 that has a threaded hole on a back runner to install a vacuum fitting if your carburetor doesn't have one?
I did find a threaded hole in the back of my 2101 intake manifold. I purchased a "Y" fitting to thread into that and that will give me my two lines for accessories. One branch will go to the check valve and the other branch will go to other accessories through the firewall. I'm still not sure what size vacuum hose I need to connect to the vacuum advance port on my distributor. 3/16" seems too big...is it 1/8"? But then the connection for the "timed/ported" vacuum on the carb is at least 3/16"...a 3/16" line is pretty tight. So I'm guessing I need to make a 3/16" line squeeze on to the fitting on the car, then buy an adapter to reduce the line size down to 1/8" to connect to the vacuum advance on the distributor?
I looked at that document by Dr. Rebuild, but I am eliminating that solenoid loop thing. Plus, the Dr. Rebuild document does not give line sizes....
From: At my Bar drinking and wrenching in Lafayette Colorado
Why are you wanting to use ported vacuum to your distributor? Do you want the car to run as poorly as it did from the factory, or are you needing to pass an emissions test..?
Why are you wanting to use ported vacuum to your distributor? Do you want the car to run as poorly as it did from the factory, or are you needing to pass an emissions test..?
Nope - my mistake. I called it the wrong thing. I'm connecting it to the spot you advised on the forward passenger side of the carb. That is manifold vacuum as you recommended. I'm just trying to get the correct hose sizes.
You posted alot of pics of the holley carb you aren't going to use, but none of the q-jet you plan on using. There are 2 different ones for 70 L46 as I posted above. Hoses and routing differ.
I think I've found the answers...I think I found that all vacuum lines on this car were either 5/32, 7/32 or 9/32....so, I'm just going to buy some of those sizes and it should become clear. I will have to adapt as the connection on the vacuum advance is clearly smaller than the connection on the front of the carb...but at least I'm a step closer.
I think I've found the answers...I think I found that all vacuum lines on this car were either 5/32, 7/32 or 9/32....so, I'm just going to buy some of those sizes and it should become clear. I will have to adapt as the connection on the vacuum advance is clearly smaller than the connection on the front of the carb...but at least I'm a step closer.
I had a 70 L46 for 45 years. Know them pretty well.
If the fitting on the front of the carb isn't the same size as the vacuum can nipple, your using the wrong port.
Don't know if you read the posts, but i've asked a few times which original Q jet you are using. Pic would help.
Also posted a pic of the correct hose routing for one of the 2 carbs use
I had a 70 L46 for 45 years. Know them pretty well.
If the fitting on the front of the carb isn't the same size as the vacuum can nipple, your using the wrong port.
Don't know if you read the posts, but i've asked a few times which original Q jet you are using. Pic would help.
Also posted a pic of the correct hose routing for one of the 2 carbs use
Hi - I have the 7040207 carb. I had it rebuilt by Lars and he told me to connect the vacuum advance to this port on the passenger side front port (seen in this picture just above the fuel fitting). That port is definitely larger than the vacuum advance fitting.
Hi - I have the 7040207 carb. I had it rebuilt by Lars and he told me to connect the vacuum advance to this port on the passenger side front port (seen in this picture just above the fuel fitting). That port is definitely larger than the vacuum advance fitting.
see my pic above. That's a very original 7040207 with correct hosing. The original had a short hose from the carb port to a metal advance tube, then continued to the tcs. I had that tube reproduced a few years back. Can post link.
You aren't using tcs so you want to run from carb to vacuum can with 1 hose.
The original short hose from the carb to the tube WAS slightly larger.
You definately can use 1 diameter hose that fits the vacuum can to stretch fit on the carb tube.
Thank you sir. It appears the connection at the distributor should be 5/32 and the connection on the carb should be 7/32 (I now have hoses of both sizes and they fit well that way). I'm afraid that stretching the 5/32 hose over the 7/32 fitting might be too much? I can try...otherwise, I might use a size adapter between the two. I think that should be ok?
Engine vacuum connections with Quadrajet
