MSD Ignition box
 

Can you get away with running a 6AL or do you have to have a 7AL. This is a 350 TPI 245/281 combo. Any advise would be appreciated.

Re: MSD Ignition box
 

I have had the same MSD 6T ignition box in my low 10-high 9 second bracket car for over 30 years, with zero issues. And I used a MSD 6AL in my 85 Mustang Stocker, but have never used a 7 series box, so I can`t say if a 7AL may potentially be any better. Certainly didn`t notice any downfalls with the 6 series.

Re: MSD Ignition box
 

Do you have it already?

Re: MSD Ignition box
 

Good morning to all,
Yes you can certainly use an MSD 6AL box, the 7AL " might " be slightly better in overall performance, but the 6 box will work. Over the years I've found the 6 series boxes to be the most reliable. That's what I've found, good luck with your racing season.

Respectfully,
Henry Kunz 1534 H/SA

Re: MSD Ignition box
 

I bought a bracket car from a friend of mine two years ago and it had a digital 6 plus in it and worked great . I completely rewired the car last year and put a 7 AL box in it that I had and it didn’t run any different .

Re: MSD Ignition box
 

Mike I have a Digital 6 in the Corvette. Works fine. How’s the car doing? Mike McMahan

Re: MSD Ignition box
 

I have a 7 AL2 in it now but I am going to replace it because I think it has a problem. At 6300 it acts like it's on a rev limiter and I allready replaced the distributer and wires so it's next.

Re: MSD Ignition box
 

Hey Mike, what kind of shifter do you have? A few years ago, I had a similiar problem and it was my turbo action line lock button that wasn't fully disengaging. I had to push on the wires to ensure the little red button was fully out.

Re: MSD Ignition box
 

I replaced a 7AL2 with a 6AL between rounds after having the car shutdown on return road. Before it shut off the tach was jumping all over the place and would barely run.
I was racing an index class using weight to run the index. I didn't change weight after replacing with 6AL and ran exactly the same ET.
This was with a ZZ4 engine making around 380 hp . 11 second Chevelle

Re: MSD Ignition box
 

Make sure your coil matches the box you are using.
Chart:
https://www.holley.com/brands/msd/pr...gnition_coils/
There is also a difference in some of the distributor pick ups and boxes.
I think it is analog vs digital. ran into a couple of customers with match up issues a few years ago.
Make sure they are compatible.

Re: MSD Ignition box
 

Adger, that is an interesting chart. I have run the Pro Power coil on every car I have had for 40 years but they all had a 7 AL2 Ignition. I wonder why that coil won't work with a 6 A ignition.

Re: MSD Ignition box
 

Mike,
I wish I had an answer for you. I've had customers that ran into the same issue. Started quite a while ago with a Circle track customer Up grading and I another recently that had a distributor that wasn't compatible with his box.
If I got this right his box was a digital 6 and the distributor pickup was for an analog box. I have 3 coils that I kept with our dyno and a couple boxes. I always liked to dyno with as much of the customer set up as possible.
I've run 7 boxes in all my own cars, never any issues. I have noticed that the 6 boxes have a rev limiter that isn't as harsh as the 7's.