Timing or Carb or Vacuum booster for the brakes?

[MNMopar]

I haven't been into the old cars for oh I'd say about 15 years. That being said I may have forgotten a few things. But here goes.

My 73 Dodge Charger with a Holley 600 and Edelbrock 318 Streetmaster 4 barrel intake. MSD coil and Headman Headers to dual exhaust is driving me nuts. I got the car to idle nicely after I rebuilt the carb and connected some exhaust so I had some back pressure. I got out the timing light  put it to 8 degrees Before tdc. And the thing ran even better but a little rich. I pulled the hose off the distributor while I timed it (remember that from somewhere). Started like a champ idled like a champ, put it into gear dropped in rpms a little but not much. The brakes were pretty mushy even though I completely replace ALL brake components except master cylinder and booster. And bled the crap out of it! But it was running good enough to move it around no open road or anything but running. I'm trying to fine tune the carb because the gas pouring out of the tail pipes is killing me! Get it running better, and less gas coming out of the pipes. I go to crack it open and it coughs and dies. I adjust the floats and it is better but not opening up with out a little cough. I put it in gear and give it enough gas to break the back tires loose and it gets up to about 2500-3K rpm and kills. I've done just about every kind of adjustment to the carb and am getting no where, no better sometimes worse.

Do I need to redo the timing? I could have swore timing would not change regardless of what is happening with the carb.
Am I flooding it or starving it? Could it be the timing chain way too loose, like about to skip a tooth?

All I have running for vaccum lines is one to the Booster from the manifold. ANd one to the vacuum advance. Pictures will show it. ANy help would be great thanks!

[hemigeno]

Lemme move this thread over to the Engine section where the Mechanical Guru's hang out...

I know you've stated what the initial timing of the engine was (assuming that's at idle), but what is the total timing at around 3,000rpm or so?

There are guys on here who can really work magic with Holley's, but I've honestly had better luck with the Carter/Edelbrock style of carburetor.  Soooo, I'm not much help with those.

[Corellian Corvette]

Make sure you're setting your idle speed to the correct setting IN DRIVE. Since Automatic cars don't idle in neutral, doing any adjustments in idle speed or in mixture in Neutral will not put you in the right place.

I'm not sure what the weigh/spring combination is in your distributor, but setting at ~ 5 deg BTC is very safe and will get you in the ballpark.

Remove the vacuum advance, plug the vacuum holes in the carb (so you're not getting a leak) and set to 5 deg BTC and somewhere less than 800 RPM (this will insure you don't have any weight advance going on). Then, plug the vacuum advance back into MANIFOLD vacuum which should raise your timing. While still in neutral, rev the engine and listen for any detonation/pinging, just to be on the safe side.

Now that your Vac advance and base timing is setup, put the parking brake on, set some wood behind the wheels, and put the car in reverse.

Most automatic V8 cars will want your low idle speed ~ 650 rpms. When you put the car in PARK or NEUTRAL, it will probably jump back up to about 900 – 1000.

Now you can set your mixture screws. Turn your idle air bleed screws in until they seat, then back them out 1 – ½ turns on both side. This will give you an equal baseline.

From there, with a Vac gauge and TACH hooked up, turn the screws out ½ turn – you should see the RPM increase as well as the vacuum improve. Turn both screws equally, give the car a second to adjust. If your idle speed is not increasing buy turning them OUT (richening them), then try turning them IN ½ turn (lean).

Either way, you SHOULD notice a point where the car starts idling rough, or stops improving. You want to hit the sweet spot where you are as lean as you can be with the best idle. Once you find THAT spot, turn the screws IN ¼ turn. That's called "1/4 turn past lean roll" and the idea is to take underhood and air-cleaner airflow restrictions.

Since your mixture will affect your idle speed, once you've set the mixture go back and make sure your idle speed is correct.

Otherwise, I will 2nd the opinion stated - if you're driving this car on the street, get yourself a nice 600CFM edelbrock. They are SUPER easy to tune, with one of the best tuning manuals I've ever seen (the factory instruction manual is great)

While I will never debate your loose max HP over a Holley, I have converted many people to Edelbrock as it's a much better street carb. Considering that basic Carter design was used on almost ever 4bbl car of the era - I'd say it's pretty well tested.

[MNMopar]

Thanks, I knew there was a much more involved method than what I was doing. I do have a thermoquad sitting around maybe I should rebuild that. But I will definatley look into the 600 cfm.

[hutch]

Thanks, I knew there was a much more involved method than what I was doing. I do have a thermoquad sitting around maybe I should rebuild that. But I will definatley look into the 600 cfm.

how did it turn out?  Let us know how you are doing with adjusting your setup, this is a pretty common issue for many old car fans.

[MNMopar]

My ThermoQuad was in much worse condition than I had thought, so that is out the door. I am having issues with the carb again so i will need to address that issue first. I adjusted the timing to better time it in gear and that did help. But now it's not running because I got so much crap for not cleaning up the engine compartment or atleast half ass painting the engine before I put it in. So out it comes and on to cleaning up the engine compartment.