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MSD igniton system. Is it worth it?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Toad, May 20, 2001.

  1. Toad

    Toad 1/2 ton status

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    I have a couple of questions about the MSD ignition systems. I have a 76 with the original 350 hooked up to a TH350 and the stock HEI system. Will an MSD ignition make a difference? If so which is the better one for a daily driver? OffRoad or 6A? Other? Would I need a rev limiter to keep the engine from over reving? What is the max rpm for this engine?

    I am looking to get more power, better combustion because of polution laws, better gas milage and a smoother running engine.

    If any of you have any experience with these let me know.

    Thanks.
     
  2. Sparky87k5

    Sparky87k5 1/2 ton status

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    I use the MSD 6A with the remote adjustable timing option. Allows me to adjust my timing 15 degrees from the drivers seat. I set the timing to factory specs less 7 1/2 degrees and the adjustment dial @ 0. After everything is set, I dial in 7 1/2 and still have 7 1/2 to go if need be or retard 7 1/2 if I get a load of bad gas or pulling too hard on a hill when towing. MSD sure helps with the starting on cold mornings, and I have noticed a much smoother running engine. I run on the lean side for fuel economy and have no problems with plug firing. Really am pleased with the MSD ignition systems. I mounted mine on left inner fenderwell.
    [​IMG]<P ID="edit"><FONT SIZE=-1>Edited by Sparky87k5 on 05/20/01 05:03 PM (server time).</FONT></P>
     
  3. K5_73

    K5_73 Registered Member

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    As far as ignition is concerned, MSD has a pretty big share of the market. They make all upgrade parts for your HEI, mainly the coil and the module. The 6 series iginitions are probably their most popular, and which one you should get really depends on what you're gonna do with your rig. The offroad has more vibration resistance, and is a little more watertight than the 6A, but even the people at MSD will tell you that the 6A is fine for most offroading. As far as the rev-limiting goes, they do offer models that have it, and they use modules to change the limit, or you can buy a module selector, which lets you turn a knob to pick the limit. Concerning your question about rpm's, if you have a stock motor, you probably are making most of your power at the lower end of the rpm spectrum, so revving it really high won't do any good. I'd say (someone please correct me if I'm wrong), but I wouldn't consistenly peg your motor much past 5000 or so, since you're not getting any real benefit as far as power goes. Hope I covered most of your questions, and good luck.

    Stupid hurts
     
  4. K5_73

    K5_73 Registered Member

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    I guess I forgot to cover the whole power subject....The stock HEI is generally said to fall off around 4000-4500 rpm's or so, and the MSD units (Accel makes them too) are supposed to have a strong spark much past that (I'm thinking something like 6000 or so). As far as a measurable power increase goes, it's hard to say, so I'll leave that for someone else.

    Stupid hurts
     
  5. Sparky87k5

    Sparky87k5 1/2 ton status

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    Running a stock 350 or even mildly modified much past 5000 RPM's is asking for trouble. Sure you can do it, but in a K5, it makes more sense to build for low end torque which means your horsepower curve will be down low, usually a max of 45-4800 RPM's. I'm running a roller cam, modest duration and reasonable lift (I=457 & E=482) and build maximum torque @ 3500 (412ft.lbs.) and 335hp @ 4600 from a 9.1 383 stroker.

    87 K5, D60 & 14FF, 5 sp & NP208 & 383 stroker. Build it Bulletproof and take it fishing!
     
  6. Toad

    Toad 1/2 ton status

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    Those are great reply's. I kept seeing them offer the rev limitor with all the systems but I kept wondering why I would need one.

    I was hoping to buy one and then swap it to my next motor. Hopefully a 383 but I will have to see how funds are when mine dies. I plan to keep the stock one as long as possible which being 25 yrs old may not be much longer. I think the rear main seal is bad.

    I only drive about 12 miles a day on it (120,000 miles on it) but when I do take it out off road/camping I want good performance.

    That looks like a sweet set up Sparky. Will that 9.:1 run on 87 octane?
     
  7. K10

    K10 Registered Member

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    I run a MSD 6AL which has a built in rev limiter. I noticed a difference in power and mileage when I installed mine. I like having the rev limiter so I dont have to worry about RPMs in the mud and other places.

    <A target="_blank" HREF=http://nick.rockcrawler.com>http://nick.rockcrawler.com</A>
     
  8. extremeblazer

    extremeblazer 1/2 ton status

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    I run the MSD 6AL with built in revlimiter. I noticed the truck starts quicker and idles smoother. The revlimiter workes great if your in mud. It helps to keep the rpm's from getting out of control when the throttle is on the floor spinning in the mud. With out it you must keep a constant eye on the rpm's and they can sky rocket quick when the back tires are not grabbing anything. I also had an MSD box in a 71 chevelle SS 454 that fouled plugs because it burnt oil. I cleaned the plugs about once a week after the msd box was installed I drove the car for about six months and never fouled a plug. It burns much cleaner.
     
  9. Chaz88K5

    Chaz88K5 1/2 ton status

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    i have had problems with the msd off road box...i was pressure washing my motor off and the box got wet...i dident spray it directly at the box and when i tried to start the truck back up all it would do was just crank for days....so i sent it back and got another one....but havent had a chance to put this one back in

    [​IMG]
     
  10. Toad

    Toad 1/2 ton status

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    Hey, thanks again for the replies. Now that you mention mud I can see the need for the rev limit. I don't do a lot of mud, but all it takes is once right. I was wondering about the water thing. What if you come to a water crossing?

    How far does it have to be from the headers, etc..? I was thinking of mounting it up on the firewall some where. Maybe by the AC/Blower motor.

    At least it sounds like it works. I know I can trust my fellow CK5'rs on things like this so I'll see about picking one up. Thanks.
     
  11. Sparky87k5

    Sparky87k5 1/2 ton status

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    I run 87 octane for all driving except when I'm heading into heavy mountain country towing my travel trailer. I then fuel up with 92 octane and dial in another 3-4 degrees of timing. Really runs well then and pulls like a bear in the hills.

    87 K5, D60 & 14FF, 5 sp & NP208 & 383 stroker. Build it Bulletproof and take it fishing!
     
  12. CaptCrunch

    CaptCrunch 1/2 ton status

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    I run a 6a Offroad MSD box, msd coil, and wires, and a holley HP module and am happy w/ the set up. If was to do it again would probably just get the coil and wires and module and be done. The HEI is a pretty good sytem up to the 4500 line... the msd does make start up a lot easier and the offroad box is different then the regular 6a. It sparks much like the Jacobs box and is suppost to be a bit more gas effiecnt because it shoots smaller muliple sparks per a second instead onf just one full powerful spark. Helps combuste better (read better emissions and mpg) Either way it is a good buy... better then a TBI spacer and K&N filters IMO... but a bit bit more cash... oh yeah.... open up the plugs to .060 for the best power and milage.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  13. riz

    riz 3/4 ton status

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    <font color=purple> Absolutely !!!!!!

    L8r,
    . Riz . <A target="_blank" HREF=http://www.geocities.com/rizmonkey>http://www.geocities.com/rizmonkey</A>

    [​IMG]
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    I'd say leave the HEI in place. The only advantage I can see with the MSD is the easier start up, as people really seem to feel this helps. Anyone that has installed an MSD, and has replaced plugs and wires at the same time, is not qualified to say that the MSD makes a difference. More often than not, plugs and wires need to be changed, and make an immense difference. The Ignition system is something that should be set up one time, and then forgotten, barring spark plug and wire changes.

    The added wiring alone from the MSD, as well as the possibility of it failing, and being one more item to troubleshoot when your vehicle won't start,. is not a benefit in my opinion, especially when you are miles off road and your truck won't start.

    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     

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