Im not sure what you mean. I did a vacuum test... it was holding vacuum at 18.5 at idle. Is there another way I should be performing the test? How do I isolate the brake booster? I’m sorry if I’m ignorant to it.

 

2 ways of doing this.
Motor off pull the hose to the booster, plug the vacuum side start motor and see if it runs better. You may need to lower the idle speed to tell.

Motor running pinch off the vacuum hose with vice grips and see if motor runs better. Again may need to lower the idle speed to tell.

Did you try the smoke test to look for vacuum leaks? Check out YouTube on this test.
Dave ----

 

Ok I’ll plug the port on the tree where the booster line connects later and see what that does.

I didnt do a smoke test. I honestly thought when I connected the vacuum gauge and it held steady that I was good.

 

I think you had a reading of 18 hg but what if it should be 19 or 20 hg?
Dave ----

 

Ok, I'm on it today.

Thanks for responding, i really do appreciate the help. I could have never have done any of this without you all.

 

Ok so first thing I did was pull the hose connected to the brake booster and connected that end to the vacuum gauge and got a pretty steady reading at 18. I did not see any change to RPM once connected.

Then took that hose and disconnected the other end of it from the tree behind the carb and attached vacuum gauge and got 18 again. Maybe a smudge higher.

Originally did the test connected to the pcv port on the tree. Everything seems to match and no change in rpm.

 

What does "pretty steady" mean though, exactly? The gauge needle should be rock steady. I haven't followed the thread closely or anything, may not fix the problem, but it's worth tracking down what's causing that. Is it sloooowly wavering a 1/4" or, is it bouncing an inch or two in time with the RPM?

 

No change with it in gear and turning the steering wheel with the Brake booster disconnected?

 

It was between 18-18.5 the entire time.

Didn’t do that so just went back out... with booster disconnected and vacuum gauge plugged in it’s place the vacuum dropped from 18ish to 15 and below when I tuned the wheel and yes, rpms dropped and stalled.

 

This rules out the brake booster and the rod seal to the master cylinder. At this point, I would say the carb is faulty. If you are getting 0.5 HG waver in vacuum reading and since you are not getting any adjustment on the idle mix speed on one venturi it is pretty indicative you have a carb issue. At his point, a carb rebuild or replacement is on the horizon. If you choose to go the route of replacement I would not install another Edelbrock and use either a Summit M2008 or Holley carb.

 

Thank you! I’d probably spring for a Holley. Do you have a suggestion for which model on my auto 460?

 

Unless you are determined to use a Holley I would give a long hard look to the Summit Carb. The Summit carb is actually a Holley, a Holley 4010 to be exact updated, improved and made by Summit.
The Holley 4010 is based off the old Autolite (Ford) 4100, in fact, the same engineers that designed the 4100 for Ford designed the 4010 for Holley. The 4010 was designed for a few reasons, one was marine applications as it met U.S coast guard regs at the time whereas the Holley 4160/50 did not it also has annular discharge boosters (like the 4100 did) allowing for a more responsive fuel signal and improved efficiency. The 4010 Holley was introduced in the late 80's, besides not looking like anything like a traditional Holley, initially, they had some teething issues with vapour lock initially that combined with the non-traditional design and the move away from carbs to aftermarket and modified OEM EFI systems left it with less than stellar sales and Holley dropped in the late 90's. Which was a shame as the carb really is the most advanced of aftermarket carbs on the market, it had the potential be a real game-changer but poor timing, initial vapour lock issues and Holleys failing fortunes at the time the carb never got the support or market awareness it deserved.

In the mid-2000s Summit licenced or bought (not sure which) the carb from Holley and branded it their own. The Summit carb is Holley carb that is patterned after the old Autolite 4100. The 4100, in my opinion, is likely the best 4bbl carb ever made for a street application.
So have a hard look at the summit carbs. For your application, since you are bog stock this is what I would use from Summit. The summit has the advantage of comming with full set up and tuning instructions.
https://www.summitracing.com/int/par...s/applications

As for a Holley, this is the guy I would use

https://www.summitracing.com/int/parts/hly-0-80457sa

 

Thank you for all the info. Was reading a lot of older threads and there seems to be a lot of love for the edelbrock as well. I know I have a 1406 that seems to have failed, but I have no way of telling how old it is... it’s tempting to just get another since I’m already set up with it and familiar with it. Since I’m very much new to working on this kinda stuff it’s a bit more intimidating to install my first carb and it be different than what I have.

 

The Holley and the Summit will be plug and play and will require far less monkeying around than an Edelbrock will. Both the Holley and the Summit (which technically is a Holley) really are designed for Fords.
Ford has been using Holley carbs continuously since the model T till they were replaced by EFI. In fact, the first use of the 4150 was in 57 on the Ford 312 Y block.
The Autolite and Holleys share many design similarities and some parts will even interchange between them, there was an is a common design philosophy between Ford and Holley carbs and I'm sure there was some collusion between the 2 during the design process of the 4150 and 4100.

Edlebrock carbs are the continuation of the Carter AFB and AVS carbs which were primarily fitted to Chryco vehicles. Much like how the Holleys are plug play on Fords the Carters tend to be plug play on Mopars.

Te advantage od the summit is it comes with a full-on book telling you all you need to know for instaling and tuning the carb and it is just a good introduction to carbs in general.
For the novice, the summit really is the best way to go. And it has the advantage of being the least expensive.