I have the 4160 on a 289. I just got the engine started after it was rebuilt and I am trying to tune the carburetor and set the timing. Could somebody walk me through what I should do in what order? I have been reading a lot about curb idle, mixture screws and float levels. I really do not know what I am doing and am confused on where to start.

Do the mixture screws on the side of the carb adjust the same thing as the screw for the curb idle? Should I set the float first then try to get the rpms to around 500? How do I check that the choke is full open?

These are the types of questions I have been asking myself and some help would be greatly appreciated. I have ordered a book specifically on this type of holley carb but it will not be here for a couple of days and I just can't sit still.

Another question not concerning the carb. There is a hiss behind the dash when the car is running and for a few seconds after I cut it off. Is this a leak in the vacuum system? What should I check?

 

For a benchmark to start from.

Set the timing first.

Adjust the mixture with the aircleaner on

Turn the mixture screws all the way in (do not overtighten them)
then turn both out 1.5 turns
If you have a vacuum gage have it hooked to a full vacuum source, otherwise you have to do it by ear.

turn out 1 side or the other out until

a: the vacuum stops rising or
b: the rpms do not go any higher.
Repeat on the other side.
keep doing this until it starts to lower rpm/vacuum reading
you are going to have to adjust the idle lower a couple of times.

Once the timing is set and the mixture screws are dialed in where you want them
have another person get into the drivers seat, apply the brakes, put it in drive and set the idle, Unless it is a manual then just set the idle in nuetral.

I would check the brake booster (if you have one) other wise disconnect and plug all the other vacuum lines 1 at a time and figure out which vacuum line is leaking.
It might be a good excuse to replace all the vacuum lines with nice new ones.

 

Is the vacuum line from the carb to the distributor a full vacuum source or should I use something else?

I do have a new brake booster. What should I check? I have already replaced all the vacuum lines under the dash.

 

Should be ported. You want to use a vacuum source that comes from under the throttle blades.
As far as the brake booster I would disconnect it (plug the line of course) and see if the hissing is still there. If it is not then the booster has a leak at the diaphram I would think.
Look into the booster first. If plugging the line stops the hissing, leave it plugged, set the timing, tune the idle mixture and set the idle.

Hopefully there is a warranty on the booster.

 

With the car running, the break pedal is really stiff. Wouldn't it go almost to the floor if there was a leak in the diaphram?

 

Nope, you have a bad booster. It is providing no assist.

 

Is there any way to repair the booster or do I need to buy a new one? Are they sold separately anywhere or do I need to by the booster and the master cylinder as a unit?

 

Wait, it is still hooked up, right?

If it is and the pedal is that stiff, the booster is gone. You can get a replacement without replacing the master.

If the vacuum hose is not hooked up when you experience the stiff pedal, that is normal. Just listen to whether the hissing is gone.

 

Its the brake booster. Thanks for the help.

Now for the replacement. Is there any difference in brands. The one I have is from SSBC and came with the brake upgrade. It is out of warranty. I have found a couple on ebay for around $100. Would it matter if I purchased a different brand?