After reading another "How to built max performance SBCs" I wonder if I should invest in a complete MSD ignition set for my 383......Beside the theoretical advantages this system may have over the stock thunderbolt IV is there really a difference in real life operation that justifies the 800 or so $ for the system? Or is a benefit only achievable with engines revving beyond the 5K range, where the stock module runs out of spark?
I am curious about your opinions and experiences!

For the ones having read my last weeks post (383 perf. problems):
After bumping up the timing to 36 total I gained 200 rpms..nevertheless have fully ported Sportsman II heads on order which will bring my revs up to the 5250 I need for building max power with my cam.......thats why I need to know if I will be ok with my stock ignition.....

I have always used the MSD's on street, race and boats. I feel they fire the plug hotter and keep them clean at lower speeds.

The last two I did I used MSD dist. with Crane ignition. I think Crane is a little better. Can't prove it, but they are a more modern system.

I did have one MSD box go south on me though. Sent it back to factory and had it fixed.

no!

up to 7000 rpm 's gm-hei is cool.

msd is only good for retard systems -like nos or charger

if I were you I would just replace the wires and put a better coil thats all.

there was a test at hot rod magazine back in 90's.there was almost no difference between 'that times' best aftermarket distributor and gm hei.

I will never have an MSD distributor on a boat again. Had complete system, 6M box, distributor, coil and wires. The distributor is not designed for marine use (factory tech confessed after several calls). The cap and internals will corrode on a daily basis, all the do is put 2 vent holes with screens on the automotive version and call it marine. I swapped it out for a Mallory marine distributor and never had another problem. The 6M box help keep plugs clean during idle and can be used with other distributors.

For about the cost of a cap and rotor, MSD will take your used distributor and totally rebuild it; cap, rotor, gear, bushings, magnetic pick-up, etc,----ALL the internal parts replaced!!! So you get practically a new distributor for roughly the cost of a cap/rotor-----hey, if you're going to get a new cap & rotor you might as well just send it into MSD every year and basically get a brand new MSD distributor for about the cost of a cap/rotor. Mine will be sent to MSD this fall.

Preuni,
I do agree with the corossion deal alot. I use to put them in all of our big engines. Not the case anymore. the down time because of sending the MSD dist's and boxes back to MSD was not worth it to us and our customers. Keep this in mind to, Mercruiser used there dist's all the way up to 1000 hp. Most aftermarket engine builders use Mercury as well, Teague, Sterling, Cobra , Innovation, etc.... Also if you were to break a cap or rotor or lose and ignition module, you can usually go into any well stocked marina an get parts. Most of the marinas here on the Chesapeake Bay dont stock Mallory ar MSD dist. parts like caps, rotors, pickups etc...

The choice is yours. Good luck.

Pwrbt33

Unless your twisting the engine 8 grand there's no real advantage,in my opinion. I've seen too many box failures both in boats and on my buddy's dyno. Nascar doesn't even use them. They take the boxes send them to Nelson Specialties in North or South Carolina (I forget) . They inturn dump the contents out and replace everything with better quality components. If you want a neat setup use the Thunderbolt ignition from Mercury and a factory Ford coil #DG-5. It gives you 40,000 volts My personal opinion is they (MSD's) are not even worth the powder to blow them to hell

Keep your stock thunderbolt ! Your boat won't go any faster, It won't idle any better, It won't run any cleaner, It won't start any better, but you'll be out a lot of money & have more head aches !!

Bo knows

Well, it looks like several of you guys really dislike the MSD equipment. I certainly value all of your opinions and trust that they are based on what you have experienced with MSD. I bought my boat used and it already had the MSD billet distributors and ignition boxes. I sold the engines and built new ones and I also sold the MSD ignition boxes, but retained the MSD distributors. I added a new MSD crank trigger system which allowed me to removed the magnetic pick-up within the distributor itself. Strangely, when I initially purchased the boat I had it tuned up---i.e. cap, rotor, plugs, etc, and as we timed it with a timing light we discovered that one engine would retard itself as we bumped the rpm up-----really weird! From there we tried EVERTHING to find out why it was doing that i.e. taking the distributor competely apart, checked cam for movement, swapped coils and MSD ignition boxes with good running engine, checked timing chain, even used another timing light. About the only thing we didn't do was swap distributors with the good running engine because we had taken it all apart and couldn't see/find anything wrong. We never did find out what the problem was because it was near the end of the season and I already knew I was putting new custom built engines in it over the winter and that included new crank triggers from MSD. Later in the spring we had both engines dyno tested and they both ran without any problems. Then we put them in the boat and they still ran fine. The only thing we think did the trick were the crank triggers----in other words we think the problem was with the magnetic pick-up within the distributor. I bought new Crane ignition boxes to replace the MSD ignition boxes I had already sold. What I am saying is that I haven't really had any reason to get rid of the MSD distributors as of yet. Perhaps it because of where I do my boating----FRESH WATER! I must admit that looking into the internals of the MSD distributor that it DOES look awefully rusty inside and that is why I am sending mine into MSD. I found out from a fellow boater that MSD will totaly rebuild them for about the price of a new cap and rotor---which I believe that is a pretty darn good deal in my opinion. It may NOT change the fact that it may still be a poor distributor for marine use. Also, correct me if I am wrong, but I been told that if your MSD ignition box breaks or malfunctions that all you have to do is send it back to the factory and they will replace it with a new one at NO CHARGE. I also know that the Merc Thunderbolt is a very good ignition, but I don't think they're a billet distributor and it may not make any difference and perhaps you guys can enlighten me/us on that. We did hook up one of my Crane ignition box to my cousins 460hp 454 while it was on the dyno--------he had the stock Merc Thunderbolt distributors and we ran the engine up to about 5300-5400rpm on the dyno. He showed NO GAINS from the stock Merc Thunderbolt distributors with the Crane ignition boxes vs. the stock Merc Thunderbolt distributors by themselves! He was seriously thinking of purchasing some ignition boxes for his distributors but the dyno showed him the truth and saved him some $$$. So I am NOT against the Merc Thunderbolt distributor---it's just that I already have the MSD billet distributors that came with my boat. Just curious from you guys that know; where do some of these Merc Thunderbolt distributors run rpm wise? What kind of RPM's do they see? Does Merc use an ignition box with lets say their 900SC ??

Anyway, thanks for the input on the MSD equipment. If I have problems with my MSD's I will certainly consider the Merc Thunderbolt distributors. Thanks---I am always learning.

I'll keep my story short.

I kept the TB ignition on all engines except the present one. They appear to be the lowest maintenance ignition to have. But it would not cut it on this motor. Saw 30 lbs more torque from MSD box alone. Plugs stayed clean instead of fowling to oblivion. Teague and Nickerson recommended the MSD box in this application. In an older Merc spec sheet, the 900sc listed CD ignition. Whether it is MSD or not, I don't know, but its not regular TB (inductive). I am just trying to share the experience that the MSD box cleared my problem on an equivilent 900sc motor. I really think blower motors need them due to the rich mixture they run and the high effective compression ratio.

I have heard the storys of MSD distributor corrosion issues. That is why I did not replace it until I wanted locked out timing and had to. I also needed a smaller distributor to fit behind intercooler.

With most pump gas NA motors, I can't imagine why one would toss the TB distributor and module, they work great. But after the difference that I have seen, I'm not going back. I never understood the importance of a good ignition sytem until these recent issues with this motor.