I have an Edelbrock #1406 that I have installed on a Ford 400 engine. The carb set for 2 years while the the engine was being built. Now that it is running, I am finding that I have a problem with the vacuum ports on the front of the carb.

There a three ports on the front of the carb, one for constant vacuum, one for PCV valve use, and one that is a timed port for the distributor. The timed port one is the one I think I have a problem with. I have the exact same vacuum at all three ports at idle, and I am assuming that I should have no vacuum at idle in the timed port, with vacuum either ramping up or opening at a certain point under acceleration.

Is my evaluation of this timed port problem correct, and can it be repaired by a rebuild, or do I have a bad carb, or am I completely confused about what is supposed to happen.

Looking for any advice or assistance that I can get.

Thanks in advnace.

Milton Crum

 

Sounds like you have the throttle blades too far opem to make it idle. The passenger side port should be ported vacuum. Pull the carb off and see how far open the front plates are open. If the low speed slots are easily seen, then you are using too much throttle to keep it idling and either have a major vacuum leak or the mixture screws are in way too far.

 

Thanks for the feedback LxMan, I'll pull it off in the AM and see what is going on. The screws are out 2 1/2 turns, that is the point where it runs best, 'cept for the vacuum problem.

 

OK, pulled carb off, and front plates are as closed as they will go, vacuum slots are open, guess I am not real clear how the vacuum on the passenger side can be any different than the drivers side since they both just empty straight into the bores, anyway retightened the whole she-bang and tried it with no difference to either side. vacuum did go up to 17", so i guess there was a small leak, but still no ported vacuum.


Any suggesstions of where to go from here? Short of buying a replacement carb?

 

The left port gets vacuum from above the throttle plates and the other two draw from below them. If you hook up a gauge, are you getting no vacuum at the left port or full vacuum?

 

I get the same vacuum on all three ports, 17" at idle. When looking at the slits in the bores they didn't appear to be placed differently, but maybe the distance is subtle. the left and right slits appeared to be equal.

 

If you'll notice in the casting on the front of the carb, the left port is higher than the other two. It may draw vacuum from up higher in the throttle bore. Another senerio is that perhaps there is a crack in the casting allowing vacuum to be drawn in all of the time.

 

Ohio, I am running this same carb on a 351W that is bored and stroked to about 392. I'll preface my suggestion with the fact that I am an engineer and have spent countless hours trying to make $3 pieces of junk work because I could. I bought an MSD mechanical advance distributor and blocked off the timed port on the 1406. I have been very happy with it ever since. Just my $0.02.

Good luck, and if it doesn't work out, buy a new Holley.