i have heard a lot of good feedback on the msd ignition. was thinking of installing one in my 75. any opinions on this? also, does anyone know if it would be installable in my 90 or would it interfere with the computer? thanks

I went with an MSD HEI unit on my '79 after the Mallory left me stranded. It smoothed it out at idle and has given me trouble free driving ever since. I think it stands up to the C3 heat better.

I'd be willing to bet MSD has a unit that would work on the '90, but don't quote me on that. Summit or JEGS could set the record straight.

I have the MSD Streetfire in the '80 stabbed into a 300hp crate backed up by a 700R4 and have had ZERO issues since I changed over from the General's.  Wouldn't have it any other way!

i should have been more specific. i meant to say the 6al control box that you wire into the system. it does not replace the whole distributor just controls the spark. thanks for your quick response.

Sorry dude, didn't use that box, did the stab swap of the distributor.

put new MSD in both my oldies, no box.  Cars runs great!

I have been using MSD boxes in HP motors since the 80s. Great fuel efficiency and a "supposed" HP gain, although most likely not noticeable. The plugs also come out the cleanest out of any ignition system I have used in the past...

I have the MSD in the complete HEI distributor replacement unit.  It has all the features of the box contained in the dist.  I love it.  Darn thing works nice, and the exhaust is much cleaner with it in place.

I have an MSD 6A installed in my '69, which already has transistor ignition.  The only real difference I noticed was somewhat better starting...no increase in performance that I can feel, but with a 3-deuce 427 L71 with an L88 cam it would take a significant change to feel it.