Ron R

Other than being able to say "I have MSD Ignition" what's the real advantage of this setup? My 383 stroker is finally done and going in this week and a few people have recommended this over the stock setup.

Kellys~hotrods

Over a 70's HEI, no voltage drop off at high RPM. The factory HEI units are great, and the only short coming is that they tend to have a lower spark energy at mid to high RPM levels. If you only plan on driving on the street then HEI's will work just fine. The benefit over points is that, for one thing, you won't have to rebiuld your pionts or set the dwell every so many miles. The MSD distributors come with several springs so you can tune your ignition advance curve as well, but this usually requires a good deal of knowlege and for best results a chassis dyno to take advantage of maximum performace gains. Another advantage is that these units spark more than once during the compression stroke, promoting more complete combustion. This translates to more power, and better fuel economy. I have an MSD billet distributor, Blaster II coil, and M6AL installed on a chevy small block. These are great quality units. In the end, you have to be comfortable with the price tag and the (in reality) small benefits you will recieve.

65-StingRay

65-StingRay

OMF

You can replace the module in the stock HEI for around $70 and that wakes up a stock unit nicely (and includes a rev limiter to boot). I used this mod in my stockcar and had a reliable and strong ignition to 7500 RPM. It takes about 30 minutes to install once you have the distributor on the bench. These parts are made by MSD as well, so you can still tell everyone you have an MSD ignition without dropping all the cash for a box.

427Hotrod

MSD helps with low speed driveability with big cams and carbs and will keep plugs clean. WOT won't change much at all unless you had problems anyway. Can't hurt..but won't change the world.

I made 800+ HP with a set of 7 year old points that started bouncing at 6900 rpm. New ones went right back over 7000 with no issues.

I currently have an MSD dist and box...but the coil is a stock parts store Bosch.

A good HEI will do great too. Even stock ones do a lot better than people give them credit for.


JIM

roscobbc

My biggest surprise after installing a MSD system was the fact that the engine would fire cleanly when attempting to pull away at ridiculously low rpm in top gear (like 600 rpm!)

stingr69

Better idle/low speed and a rev limiter is about all you will get with the MSD. Nothing wrong with running one. A well set up HEI is also a good piece that won't hold you back.

I put a Crane HI-6 multispark CD on my points distributor with a stock coil and a stiff set of points. That setup runs over 7000 RPM without a hiccup.The rev limiter is set with a turn of a screwdriver. The box is hidden inside the passenger compartment so it still looks stock.

-Mark.

jackson

some find it looks "real" good.

Most boxes are wired in such a way that if the box fails you'll have a tough time getting the OE ignition back online. If & when a box fails you won't find anyone around who knows how to fix box's internals ... heck, you'll be dang lucky to find a local who can properly test it. Conversely, rare HEI failures usually easily diagnosed & fixed with parts usually on shelf at parts house.

All 3 top levels of nascar run boxes because they need one (rich carbs) ... all 3 levels allow either MSD or Crane ANALOG ... mostly msd ... all of em run 2 boxes & two coils (primary & backup) with a switch between ... boxes do fail.

FYI ... Davis UI has a good "DynaMod" module for HEI.
A good HEI is usually more than enough for many race motors.

crazywelder

MSD offers inductive HEI distributors that are ready to run without a ignition box and they offer ignition boxes which convert your ignition to capacitive discharge (CD). I assume you are asking about the CD box that is added to a OEM distributor.

With OEM inductive systems the coil is the downside because it needs to be recharged for every spark. Inductive systems use long dwell times to fully recharge, or saturate the coil. At high rpm there is less time to recharge the coil. HEI's perform the dwell time electronically and can increase the dwell time at high engine speeds to effectively improve a coils performance by ensuring adequate coil saturation. MSD or equivalant high performance coils are designed for faster recovery time. Inductive systems are good for driveability but are limited in high rpm conditions unless upgraded from stock.

MSD, Crane and other systems that use the add-on box, convert the ignition system to a capacitive discharge design (with the exception of the MSD HEI design distributors and accessories). CD is better for high performance use. CD control boxes are required for points and magnetic pick-up distributors that have no internal electronics. CD systems use a power supply driven by a full 12 volts to a large discharge capacitor located in the control box to store energy to the coil. CD systems are great at high rpm but are not so great at low rpm because the spark from a CD system is short duration. Remember the inductive system was long duration. To compensate for the low rpm driveabilty, CD systems create multiple sparks up to around 3k rpm because of the fast recovery time. The multiple spark improves low rpm driveability but cuts out to a single spark above 3k rpm. The control box does the same thing to improve spark duration and energy as the inductive system.

For a street and occasional strip car, as said, the HEI is fine and the best of both worlds.

jerrylee

[QUOTE=Ron R;1565520479]Other than being able to say "I have MSD Ignition" what's the real advantage of this setup? I often wonder if I should have just got a set up from Jegs or Summit......As for working good at low idle and turning over good..How do I know if that's with the help of MSD or my car is just running good.....Thanx...Jerrylee///

Jims66

I run a two step MSD box and distributor in my mid 10 second bracket racer (BBC '67 Nova). I feel it's kind of a must have for racing. As far as my L79 '66 Corvette....., I still use the stock GM distributor with original points set up and haven't had any problems to date (I've owned this car for 20+ years). The only ignition upgrades over stock are a set of "Taylor Spiro-Pro" Ignition Wires and an Accel cap and rotor. I kind of like to mess with the timing, dwell and carb. It gives me something to do to feel like I'm back in the good 'ole days. It beats washing the car all the time which is all that most folks around me tend to do these days.

Ironcross

I run consistent low 11`s with a box stock 1975 HEI unit in a 454 ci. LS7. I didn`t even consider the high priced parts as it was going fast enough as it stood. Results of this is that I dont get any bragging rights .....but who cares