Anyone running an MSD box with a hood tach. My tach worked fine with a stock type HEI hooked to the tach side of the cap. A friend gave me an entire MSD ignition set up he decided not to use. I tried hooking the tach signal to the 6a box direct, then with the msd tach adapter 8920. I called tech support, they said they have issues with the pontiac hood tach with no solution yet? Any ideas?

Thanks

It doesn't work hooked to the tach terminal of the HEI anymore?

The MSD distributor has no tach terminal, and the directions say not to hook up to the neg side of the coil.

There is a solution to this that I read on the PY site. I would do a search there.

Seems like it should work off the tach adapter. Do they make more than one kind of adapter?
Not sure what kind of signal the hood tachs use but, if it helps any, my original in-dash tach works off a square wave signal. I have mine wired straight to the tach terminalon my 6AL box.

Today I checked voltage at the tach terminal of the msd box. I have slightly below battery voltage with my dvm. MSD claims it should be 1 to 5 volts, and I may have a bad MSD box? Has anyone ever checked voltage at their tach terminal? What a pina! However noticeable gains in performance and economy.

If you have access to a meter with tach capable setting you can hook it up to that lead off the MSD box. I use that when making adjustments. That will tell you if the signal from the box is good or not.

I could never quite understand this problem as my original 68 hood tach that was on my Bird worked with all of the following and never an issue: HEI dist. (on the car when I bought it), I then went to a stock dist. w/points, stock dist. w/Pertronix Ignitor II, MSD dist. w/MSD box.

Now with the LeMans I bought a repop hood tach for a 67 (tall tach) and installed with the original dist. w/points and it worked fine. Now I have replaced the original dist. with the new MSD plug & play HEI dist. that looks like a stock dist. with stock appearing black cap and the repop hood tach works with that as well. Not sure why some people have a problem and others don't.

Now, in saying that the new repop hood tach works with my new MSD plug & play dist. I will say that sometimes when you first start the car, the tach does nothing, the needle is burried below 0. Then, after a few seconds it pops up and works fine. Sometimes it will take up to a couple of mins. or if you tap on the top of the tach it works fine. 7 out of 10 times it works fine without any delay, the other times I just take off and then it starts working. Almost seems like it needs a bit of juice to get it going.

Also, the fused link from the hood tach, does in fact go to the (-) negative terminal on the coil...

My hood tach also works with the MSD 6AL box.