Which one do I need? MSD6AL or MSD6A? A different one?

I am having a problem with my nitrous plugs, TR6s/Autolite104s at .035/.040 makes the car misfire badly, put not when gapped at .050 but then it misfires when i spray. So I was thinking an msd ignition would clear up my problem. Any ideas? I'm running a compression test tomorrow.

 

The "L" stands for rev limiter, it's a good feature to have as the stock rev limiter cuts fuel instead of ignition.

 

Either the 6AL or the Dig 6. I swapped from the 6A to the Dig 6 when I installed nitrous due to the increased features (i.e. timing retard, rev limit, etc). Seems to work great. Hope this helps.