I don't know that connecting directly to the coil would work, nor would be a good thing to try. With the MSD setup, the brain box is hooked up between the coil and distributor. On a conventional ignition, the distributor connects directly to the coil. Since you're playing with a lot of voltage, I wouldn't chance that without talking to an MSD tech first. But, I have a feeling you wouldn't be getting the same kind of signal at the coil any more. In the MSD instructions, it says their tach terminal puts out 12 volts, and some factory tachs may need a tach adapter to change the wave signal (compatibility issue). It doesn't suggest the tach will turn to toast, but maybe just not work correctly. By the way, I have an MSD 6-AL on my car too.

 

Many Thanks, Stovebolt.

Good questions. That was part of the reason I asked because I didn't want to blow the TIC-TOC.

The second question: "Can you hook up the TACH to the negative side of the coil just as the original?" The MSD instructions say specifically that you cannot.

Thanks again for checking your set up.

Vic

 

Thanks everyone.

now (at the risk of changing the original subject of this thread) please allow me to tell why I asked the question in the first place...

I was measuring the mechanical advance on my (recently rebuilt) 327...and discovered that I can only get about 10 degrees of mechanical advance on what looked like a stock distributor. (I am currently using a Pertronix II Ignitor..which BTW, I am very happy with).

I took out the distributor and inspected it very carefully and found what looks like an advance limiting mechanism. It looks like a pin that sticks out of the of the bottom of the movable top plate. The pin moves in a hole and (it looks like to me) that it limits the amount of travel i.e. the mechanical advance. Over the pin is a cooper-colored bushing...which limits the travel even more. The bushing is held in with a "C" clip.

I took the bushing out, re-installed the distributor and sure enough I was now able to get a few more degrees.....but not the 20 or so degrees that is typical.

As it turns out the distributor is from a '73 Chev ..which probably had very different characteristics than my '68.. This is why I am looking for a new ignition system...including a new distributor.

BTW, here is another potential replacement that I am considering:

Retrotek - Powerfire Distributor (Adjustable, Ready-to-Run)

Anyone have any experience with this one?

Vic