Carburetor and Exhaust Problems

 I've been having a few teething problems with the '68...

The first one goes like this: The car was running rich - I could smell gas when the engine was running - and it was making an obnoxious popping sound when I stepped on the gas pedal. After hunting around on the interwebs and taking to my friends in BAMA, I figured the power valve could have a broken diaphragm. 

If you're not familiar, the purpose of the power valve is to improve part-throttle drivability, air-fuel ratio, and fuel mileage¹. I have a pretty stand Holley 1160 series carburetor, so the power valve is an easy part to get hold of. Of course, the power valve that I removed didn't have any markings that gave away the part number or size....

...after tapping into the BAMA database one more time I knew I needed at "6.5" which means, in essence, that the valve opens when the vacuum reaches 6.5 inches Hg. 

Changing the power valve eliminated the "popping" sound when the throttle was opened, and with the help of you know who, I made some adjustments to the main jet and idle mixture screws. The car did sound better after that, and the overpowering smell of gasoline was also absent. Yay!

I had to do something about all the gunk on the sparkplugs. One option would be to pull each one and go over it with carb cleaner...Another option is to take the car for a drive - about twenty miles should do it. I decided to take option two, since it gave me an excuse to head over to my buddy Chuck's place. 

The next photo was snapped inside Chuck's garage. I actually broke down about ten minutes away, but we managed to get the engine re-started and I limped the '68 the last couple of miles.    

We pulled the carburetor off again, and Chuck made few more adjustments and leveled the float which made the engine sound better. But that wasn't the end of it...we also discovered that one of the bolts that holds the header to the cylinder head was missing. Oops. I had been wondering why the engine seemed to be particularly loud lately! 

It quickly became apparent that installing a replacement bolt would not be simple because the thread in the cylinder head was stripped out. We tried re-tapping the thread, and even used a bottom-out tap, but without success. There wasn't much else we could do at the time, so I drove the '68 back to Oakland, without breaking down this time. Once home, I ordered a thread repair kit off the interwebs, and installed it a few days later. This is the view with the bolt re-installed and before the spark plug wire was reconnected: 

Now for something completely different....one of the many options on the '68 Mustang was a remote control mirror at the driver side. The description of "remote" is a bit of a stretch - the mirror is controlled with a chrome-plated joystick which is mounted to the door panel at the driver side; three cables are attached to the mirror glass and allow 3D movement of the mirror. 

This option was never available for the passenger side, so it is not possible to purchase an OEM replacement or an after-market part.....but, one of the folks in BAMA gave me a spare driver side part, which I thought I could adapt to fit the passenger side. 

After taking the mirror apart and rebuilding it in...well, in a mirror image, the next step is to drill a 3/4 inch diameter hole in the upper edge of the passenger door. This hole is present in every driver side door regardless of whether the remote mirror is installed as an option. The rubber pad that goes between the mirror and the bodywork is also equipped with the hole as standard, and makes a useful template for locating the hole at the passenger side:

After marking the center with a punch, I bored out the hole in one pass with a step drill:

This is a view of the mirror after installation:

A similar 3/4 inch diameter hole must also be made at the door panel to accommodate the joystick: 

While I was at it, I also installed my custom radio control knobs. I've had these for many years, but never got around to drilling holes and making them fit the studs.