MSD 6AL2 Programmable Installed – Purrs like a kitten

If you’ve been following project Trans Am, then you may recall that I had to replace the Pertronix Flamethrower distributor because it was acting whacky. I was temporarily running a Cardone distributor with light springs in order to get by for the winter. I maybe drove the car 100 miles with this temporary distributor, but it worked better than the Pertronix at least. Just to recap, the Pertronix for some reason was retarding the timing rather than advancing when rpm’s increased.

When I discovered the MSD 6AL2 Programmable model last year, I was initially going to keep the Pertronix distributor, lock out the advance with some epoxy and replace the module with a 2 wire harness from MSD. Over the winter I found an MSD Pontiac distributor on eBay for a song. Smart move at first, then I discovered that I needed to buy another composite distributor gear because the shaft diameter used by MSD is not the same as the factory. I got a BOP Engineering composite gear for an MSD distributor.

Though they cost twice as much as a bronze gear, the BOP Engineering composite gears are worth every penny. The composite gear I was using on the Pertronix looked brand new when I pulled the distributor out.

Official parts lists:

  • MSD 8563 Pro Billet Distributor
  • MSD 8207 Blaster SS Coil
  • MSD 6530 Programmable 6AL2 Ignition Box
  • MSD 84033 Coil Wire
  • BOP Engineering PDG38 Composite Distributor Gear

I am currently using Pertronix spark plug wires. Someday I will replace them with MSD 31193 Black 8.5mm spark plug wire set.

I ran into one challenge mounting the coil on the firewall. The original plan was to bolt the coil directly to the firewall using the MSD mounting isolators. What I did not anticipate was that there was a gap between the firewall and the cowl, I would not be able to reach into this small gap and tighten the provided fasteners. I ended up fabricating a plate to mount the isolators to, then fastened the plate to the firewall using sheet metal screws. It came out ok, but if I did it again, I would mount the coil 90 degrees from how you see it now to prevent sagging on the 1 isolator side of the coil (see photos below).

I programmed the 6AL2 knowing that the timing curve is actually retarded, not advanced. What I mean is, the MSD software lets you set the all-in timing, then you can map your curve from that timing in retard degrees. I set my initial timing between zero and 600 rpm to 20 degrees retard in the software (to be at 16 degrees). I set the 650-1,200 rpm to a 14 degrees retard (to be at 22 degrees at idle).  I then charted my all-in point at 2,700 rpm to a 2 degree retard (to be at 34 degrees all-in). This makes the timing curve between 22 degrees and 34 degrees between the 1,200rpm and 2,700 rpm range. I set the timing to 22 degrees with the timing light at idle (if you are following, this is 14 degrees retarded from all-in point in the software). I decided on this initial curve for a couple of reasons; If I want to add 1-2 more degrees of all-in timing, I can without touching the distributor (you cannot advance timing beyond zero retard with the MSD software). I set the zero to 650 rpm to 16 degrees so cranking rpm timing is optimal (no more hard starting).

The MSD 6AL2 Programmable Results Are Amazing!

Since the upgrade, my engine now purrs extremely smooth at idle. When I hit the throttle then let off, the rpm’s quickly come back down. The engine also seems to burn the fuel better. There is definitely a noticeable difference between an HEI and the MSD system.

If you are chasing a special timing curve that you cannot reproduce with weights and springs, I totally recommend the 6AL2 programmable. If you like controlling parts of your car with your computer (like me), then this is also perfect for you. I’ll never mess with a mechanical advance distributor again.

MSD 6AL2 ProgrammableMSD 6AL2 ProgrammableMSD 6AL2 Programmable

4 thoughts on “MSD 6AL2 Programmable Installed – Purrs like a kitten”

    1. I believe the Tach Filter was only necessary for points style ignition systems. The MSD tach out wire should be able to be wired directly to your factory tach, that is how I had it wired. I currently no longer have the MSD ignition, instead using FiTech’s built-in ignition so now my factory tach is wired to I believe the – (negative) terminal of the coil.

  1. Excellent feedback and I can relate I have a Pertronix Flamethrower distributor, it came with my 1971 C10 GMC truck, ha ha, it may be getting replaced after reading your post.

    Question for you, have you played with the vacuum advance feature at all, or are you just relying on the mechanical or I should say the equivalent of the mechanical advance?

    1. If your current distributor is working then I would run it till it becomes an issue.

      IF you read through my blog I have replaced the 6AL2 programmable with my fuel injection FiTech, it now controls the timing, I can make adjustments from the screen right from inside the car.

      I am now using a vacuum advance built into the FiTech EFI, I just tell it how much to advance the timing when vacuum is high. It helps when your engine is not at full throttle so the engine doesn’t burn as much fuel. I don’t let the vacuum advance go too far though in my case, last thing I want is pinging, but my engine tolerances are a bit tighter than normal.

      When I had the 6AL2 you could also add additional advance/retard based on vacuum but I never adjusted that except for monitoring the vacuum. I loved the 6AL2 but I love the FiTech even more since i can adjust the timing right from within the car.

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