Stock tach with MSD ignition

[steves66]

I am thinking about upgrading my 440 stroker ignition to a MSD 6AL. I already have the Mopar electronic conversion dist kit with the orange box. I have heard that you have to buy a tach filter to make your stock tach work with the MSD boxes?? Can't you just use the tach port MSD has on their box to hook the stock tach to?

[Nacho-RT74]

A friend of mine tried to use the stock tach with MSD ignition on his 70 cuda, and didn't work

[tan top]

i have heard that you cannot use a msd with a original  tick toc tach , also i remember a few years some after market tach's warranty would be invalided if a msd was used . i remember reading ,and i think it was on this site some were , that the new re popped tic toc tach 's were compatible with an msd. but i have not tried it my self yet.

[69fuchs]

MSD ignitions require a "square wave" tach signal to make the tach operate correctly.  You can buy a tach adaptor from msd (for around $100) that will allow you to use the factory tach. 

High quality tachs like an autometer (not an autogauge though) will have the square wave feature built in.

[firefighter3931]

MSD ignitions require a "square wave" tach signal to make the tach operate correctly.  You can buy a tach adaptor from msd (for around $100) that will allow you to use the factory tach. 

High quality tachs like an autometer (not an autogauge though) will have the square wave feature built in.

Yep, Fuchs is right on the money here. The autometer tach works right off the port. 

Fwiw Steve, i wouldn't trust the stock tach anyway. The good thing is that the 6al has a rev limiter which can save your engine.  You'll luv the 6al, especially at idle and lower engine speeds. It really cleans things up and lights the fire ! 


Ron

[dodge freak]

I loved my 6 a for 8 years till I got the 7 al last summer, now I love my 7 al and think the 6 a is ok. Maybe it was getting old not sure but it idles great now even when its ice cold-45 degrees not run for a few days, with the 6 a it would stall if you were not careful for the first min. or two. Now MSD "improved" the 7 al and calls it the 7 al plus and raised the price sky high not sure if they should have did that they had the 8 box now they are about the same, think Jegs and Summit still have some new 7al box left might want to get one of those well you still can.

[mopar1]

Just bought the msd tach adapter for a 71 r/t 440 charger.Still having problems with it.

[Brightyellow69rtse]

i got the 6al too and i even got the tach adapter and i caould never get it to work right. it worked before the msd. if anyone knows exactly how to hook it up please share i just gave up on it ......Mike

[Ghoste]

I don't know why but it seems like some people have no trouble getting the factory tach to work and others have to fight and fight.  Have any of you that are fighting tried the MSD tech line?  The stock tachs may not be very accurate but it's still cool when they are working.

[defiance]

Well, I'm running a reproduction tach, so maybe that's different?  I'd have thought the function would be the same, but I guess not...  For mine, I'm running a 6A, direct from the port to the tach, no adapter or anything.  It's a bit jittery, and about 20% high (shows about 1200 rpm when it's at 1000), but it works well enough.