I've found that the best advantage to having an MSD ignition box in a street driven application is that with a less than ideal choke (which some aftermarket carburetors are known for) the Multiple Spark Discharge box causes the engine to run better during the first 20 minutes of operation when the engine is still cold, and prevents stalling too. Particualrly if you're running an intake manifold which no heat crossover such as any of the aftermarket single plane manifolds or the edelbrock "AirGap" dual plane model.

The MSD box delivers multiple sparks for 20 degrees of crankshaft rotation to each plug from idle to 3,000 RPM. That will not prevent the choppy idle that a long duration performance cam with alot of valve overlap causes, but it will prevent most of the spiting, hesistating and cutting out of the engine during cold operation which is really due to improper air/fuel ratio during cold operation, but the MSD compensates for that. This is especially noticeable with street driven cars being used with Holley racing carbs like the 4150 HP models and the 4500 Dominator models which don't offer the oprion of a choke. it helps out the most if you drive your car during cool nights or early mornings when it can take a little longer for the engine to warm up.

 

Oh, BTW the soft-touch rev limiter of the MSD 6-AL boxes is a nice feature too since it allows you to use different plugs to set your rev limiter to whatever RPM you want it at. You can even set it to 3,000 RPM if you absolutley have to bring your car to a garage and leave it there where you're concerned about employees there beating the crap outta of it. Ofcourse if they know enough about the MSD boxes and happen to have some 6,000 or 7,000 RPM MSD plugs of their own, then they can easily get around that. But not everyone is going to have those laying around in their toolbaox either.

 

If it's a street car, and you have an HEI, don't bother with MSD. I've had nightmare electrical issues with the MSD boxes.

Unless you're doing mostly racing, a well-curved HEI is more than enough and extremely reliable, and there are a lot of serious racers who still use an HEI.

There are many on this board who love MSD -- you're going to get many contradicting opinions.

 

Unless you're doing mostly racing, a well-curved HEI is more than enough and extremely reliable, and there are a lot of serious racers who still use an HEI.

:yes:

Danny,tell us more about your car,the motor and intended useage

 

You will get many conflicting opinions about MSD boxes on this board just as "658Chevy" has mentioned. After using an MSD box in a couple different cars on the street which had carbs with a real lousy choke and no choke at all, I'm convinced that no matter how good your ignition system is, the car will still run like crap during the first 10-15 minutes of cold engine operation unless you have the MSD box, since it's really due to an improper air/fuel mixture problem that only occurs during cold engine operation, and then is gone by the time the engine warms up. As I'm sure that most people here know, the engine needs a richer A/F ratio during cold operation than it does when it's fully warmed up. if you have a nice electric choke that operates flawlessly, then you have that covered, and you won't need the MSD box unless you just want it for the soft-touch type rev limiter it has. But the MSD box will NOT increase HP.

A lot of drag racers on here bad mouth the MSD boxes only because they don't increase HP, but power increases are not the advantage to the MSD box, and street driven cars without nice chokes on the carbs being used do benefit from the MSD box because of the multiple spark discharge. It DOES make a noticeable difference in cold engine operation. But it depends on the carb you're using. Some carbs have chokes that work a lot better than others, and as I mentioned in my last post, some carbs from Holley have the choke horn milled right off of them, so there isn't even an option to run a choke with those carbs. I've never had an Edelbrock carb since I don't hear good things about them, so I cannot comment about how their chokes work.

BTW, I've never had any problems with the MSD boxes, but you cannot hook a diagnostic tach to the negative side of the coil if you use the MSD boxes, because it can destroy the box. Instead, you have to connect the tach to the terminal on the bpx like it says to do in the instructions, same goes for a dash mounted tach when using the MSD box. On;y certain tachs are compatible with the MSD box, and it gives you a list of the ones you can use in the isntructions. You can also go to the MSD website for that info or simply cal them up.

Another thing about MSD boxes is that only certain timing lights are compatible with them. if you go onto the summit racing website, just about every timing light that they sell, lists a catogory of specs for that light, and in that list there's a "MSD compatible?" listing, and it will say "YES" or "NO" next to it. If you use a timing light that isn't compatible, it can sometimes end up reading the timing off of the the #3 cylinder instead of the #1 cylinder even though you have it hooled to #1. I don't know how this happens, but it does with some non-compatible timing lights. If you're using one of those with an MSD box, you'll sometimes see that the timing at idle RPM is close to the 270 degree mark on the balancer and the engine is still running fine. Been there done that.

 

Billy,the times you said the MSD basically improved cold engine operation,where any of those cars operating with either blocked off exhaust crossovers or just plain didn't have one? (like an RPM Airgap or Victor Jr)

 

Once it was with the dual plane intake that had a heat cross over, and the MSD improved it, and another time it was without a heat crossover, and the MSD improved it even more.

here's an example:

I would drive to work when the air temps were in the 60's and some days even in the 50's, and it takes me 20 minutes to get to work. The car would stall three or 4 times during the first 10 minutes of the commute without trhe MSD box. But with it, and nothing else changed, it wouldn't stall at all, nor hesistate like it had without it.

 

I've read posts from you before, BillyGman, and I do respect your opinion. I'm not trying to negate your experiences, but here are mine:

1972 Cutlass 350, HEI, Rochester, stove-pipe choke -- worked flawlessly. For a time, I had this car stored for 3 months during a Chicago winter. It started immediately without any gas poured down the mouth.

1970 Olds 455, stock points, Holley, manual choke. Once set right, and keeping mindful to ease off the choke after a few minutes, worked fine.

1969 Chevy 454, cold-blooded (blocked exhaust crossovers) MSD dizzy and box, Demon carb, electric choke. Could never, never get that Demon choke to work right. I'd set it, it'd open properly five or six times, then work whenever it felt like it. My right foot became very sensitive to engine warm up with that set up. I then took out the nightmare MSD box and dizzy, put in a GM dizzy with the right curve, and that Demon still started like and warmed up like crap.

Now, I still have the 454, the HEI, the cold-bloodedness, but have switched to an Eddy 650 AVS with electric choke. Works perfectly. Starts up, and the choke lets off just as the engine is at temp (that takes a little tuning of the richness setting). I think Edelbrock has made up for it's decades-old bad carb rep with this new AVS setup.

Another thing I didn't like about the MSD dizzy is that the insides corroded very quickly. I just took the cap off the Cutlass's HEI mentioned above and with a five-year cap and rotor, it was still nice and clean. The MSD would be covered in "green fuzz" after six months.

I hope you can gain what you need from all these posts that will help you make the right decision for your car.

 

If you have a choke that works real good, then the MSD will not offer you much benefit IMO other than the soft touch rev limiter which works pretty good too. Personally, I think Holley Chokes suck(the manual ones) on their 4150 carbs because the fast idle speed cannot be adjusted independently of the choke plate position. And so in order to set the choke plate position where it needs to be, the engine is idling at 2,200 RPM!!! That's how the Holley 4150's were that I had anyway. So I didn't even bother trying to run the chokes on them anymore.Fast idle is supposed to be more like 1,350 RPM. But One of the Holley carbs I had didn't even offer a choke since the horn was milled off (the HP Holleys are like that since they're intended for racing).

 

all my big blocks that have anywhere from a 223/231 @ .050 up to 240/246@.050 cam with Holley carbs (typical jetting 73-83 or 74/84) all start up an idle with usually no assistance when cold.No choke,no MSD but the exhaust crossovers are open.And I live in the NE
What I like about MSD boxes are they add no resale value to any of these old musclecars that I horse trade or work on for customers Every MSD box equipped car I come across gets converted back to either HEI or stock distributor with a Crane XRi and people buy up that used MSD stuff pretty quick
Most people from what I can gather buy it for the rev limiter or like the looks of the box on the firewall.
Their stand alone distributors are nice pieces though...

 

My small block Vette with a 230 dur@.050 cam started up and idled fine when cold too. But placing any load on the engine while it was cold was another story. For instance, if I tried to drive it before spending atleast 15 minutes to warm it up, it would buck, hesitate, and stall all over the place whenever I hit the gas from a rolling start, a well as from off idle when pulling away from a traffic light. I don't care to warm up the engine for 15-20 minutes every time I want to take it out to avoid hesitating and stalling. Starting it up and getting it to idle unassisted wasn't the problem at all. With the Holley 4150 carbs, a heat cross over and no MSD box, the problem was driving the car after letting it idle for just 30 seconds. It wasn't fun driving it in traffic on the way to work, and having it stall out at a traffic light when it turned green as soon as I stepped on the gas. Real embarrassing too.

The MSD box put an end to that drama. And as for me, having the box on the firewall is just another thing I had to hassle with during installation, so for me, it never had anything to do with how it looks at all. I'd rather not have to mount it at all. But for me, it has always worked very good. So it's about function, not about show. :noway: And "adding value" to the car? Well seeing is how i was never that fanatical about any of my cars being "factory correct" right down to the last nut and bolt, and down to which radiator hoses I used, I don't care if I install something that "doesn't add value" to the car. I'm not one of those Barrett Jackson type "investors". And I'm not building the car to please someone else, nor to just turn around and sell it as soon as I'm done building it either, and I never had that intention to do that with any cars I had in the past.

All of my cars including this one I'm building now, were/are far from factory stock anyway, so I care not about how much "value" an MSD box adds or doesn't add to the the car. I don't try to build museum pieces on wheels that will get roped off or placed underneath a canopy at a car show. I build my cars to race them at the track once in awhile, and drive them hard on the street, so that I can enjoy them. I build them to use the power that's under the hood. Otherwise, I don't see any point in having any car other than a fuel economy type 6 cylinder car.

I mean no offense, but driving my car like a granny for 5 or 10 miles down the street twice a month, just to park it, and sit there in a parking lot in hopes that someone will shower me with compliments about it or make me an offer that I cannot refuse so that I can strike it rich, just doesn't fascinate me, and it never did. I cannot relate to people like that, and I'm not even gonna try. But an MSD box has nothing to do with an application like that. Not for me it doesn't anyway.

 

Billy,I am glad having an MSD box worked well for you in your applications.
The point of my post is that they are over rated for most street car and race car applications.
I don't drive my cars like "granny" down the street for 5-10 miles once a month or treat them like museum pieces...not sure where you got that perception from
..and neither do my customers.
But,if I had a 632 BBC that has the potential to run 9 second ET's I would use an MSD ignition.

 

LOL...OK, fair enough. I hope that my comments didn't seem over the top. The "adding value" comment you made, had me wondering, and just a little baffled. I didn't even know that you're in business which includes building muscle cars for people. That actually sounds to me like a pretty cool biz, and I'd like to hear more about that if you care to shoot me a PM, because although I work on my own cars, I might even consider using your service in the future if any of it might apply to my specific interests. If you have a business website, please include that either in a PM, or in your next post. :yes:

But perhaps atleast some of your customers are those "investor" types that I spoke of who are always concerned about what "value" is added to their cars by the installation of any given performance parts. Or maybe some of them are those which you spoke of who might want an MSD box installed on the firewall, simply because of the way it looks.As I've previously stated, I cannot even begin to relate to either of those groups, and I won't even try to. But as for me, I'm motivated to make choices on any electrical or mechanical parts only because of performance gain or functionality purposes alone.

As far as looks of these Chevelles go, like most classic American muscle cars, they look great as they are IMO the way they came from the factory, with perhaps the one exception being the skinny tires they came with, and even a choice for wider tires is more of a functionality issue due to the need for greater traction. But as you know, these cars have subtle but beautiful body styling, as well as nice looking engine compartments even in their stock form, and if I add anything to them, it's basically due to the need of function for the most part. So any suggestion or recommendation I make to people on this board or anywhere else, is not to "add value" nor for looks (unless perhaps it's only a wheel model choice which is often a very individual thing anyway).

But even with a wheel choice, with me and my cars, the need for a moving away from the stock wheels (which I happen to like) only stems from the need for wider tires. The P315/60/15 drag radials I have on my Chevelle would be very cramped on a 7" or even on an 8" wide factory stock wheel, and such wheels would compromise the traction advantage offered by the wider tires. So to a certain extent, even the wheel choices I've made stem from a need of function. But I digress.

The MSD box thing is something that obviously the original poster of this thread will have to make a decision about, and it looks like he's heard just about all sides of this debate. Therefore, he is now armed with the information that he needs to make an educated decision, and that's what he was looking for I'm sure. Peace.