Hey guys,
The vette is in the shop(once again) having some paint work done on my new hood. While it was in there, I told the guy I've got a new distrib and ignition box to put in while she's on the shelf. He put the new MSD HEI distrib in and he called me to tell me that the MSD 6A box is not needed? I went ahead and bought a mounting bracket a while back when I bought the box but am kinda curious now. He said "unless your running at 6500 RPM's and drag racing, your not gonna benefit from or need that ignition box." He also said the factory ignition would be more than enough for what I need.

I've talked to a few more people since he gave me this info and they have had mixed reviews on this opinion. I have been told that his answer may be correct to an extent, but the thing about having the MSD box is that it will burn any extra unused fuel with the additional spark given off that the factory ignition may not be able to handle. Others have told me the MSD box is a waste of my money and to throw it on ebay and make a few bucks off of it. I mean I've got all the parts needed for installation(minus the additional wire to run to the battery from installing in the engine compartment, so putting it in would not be a big issue. But if its totally a waste of time, then I could just as easy sell it and use the money for something else? Here's my big thing...How many street cars do you see running around with MSD boxes on them? Yea, quite a few...and your gonna tell me all those cars are dragsters? I think not...but maybe its just for looks, idk?

If you guys could chime in on these issues, I'm all ears and quite interested on the truths, pro's and con's on this matter...?

PS. I know with the 6AL box, you can put rev limiter chips in, but this is not the 6AL box so the importance of that is useless...

 

Stock HEI is more than adequate, even for a track car. The 80's Chevy Power Manual used to recommend HEI as an upgrade from points for a track car. Opinions may vary.

 

Do you need one? No. Are they nice to have, maybe. I have one that came with my 71. With a moderate cam, I think it makes a difference with starting and a smoother idle. I don't plan on removing it. From what I know, it's single spark after 3K RPM.

 

Well I mean, if it helps the running of the car then I'm all for it or if it gives it a little "umpff" then I'd rather put it on. But if it helps out in no way, shape or form, then there's no point in keeping it...?

 

these are more than adequate as Scott mentioned , and readily available all over from East to West

 

A simple points and condenser system will give you as much HP as a bling MSD box at speeds of 7K RPM or less.

Gas and air makes power, not sparks.

Ditch it.

 

Sounds like the guy doesn't want to hook it up for you?

 

The 6A box in my '71 improved idle quality and low RPM operations quite a bit, but the heads I had on the car when I got the MSD box had leaky valve seals. When I put new aluminum heads on the car, I can guarantee you there would have been no difference between the MSD and the factory points ignition. I'd listen to your mechanic and go with the HEI.

 

I've installed a fair number of these over the years and I've always had feedback regarding easier starting and improved fuel economy...but it's always been anecdotal.

I have seen spark voltage drop a fair bit on older stock HEI as low as 5,000 RPM...but with the newer aftermarket units I haven't seen significant drop in the range I typically see on the chassis dyno, which is < 6,500 RPM.

The "multiple spark" aspect is pretty much over at around 3500 RPM and at that point it's really just a "helper" coil. I can't see needing it on a street-going engine, and it certainly doesn't make power.

Just make sure your HEI has a very healthy power supply and leave it be.

 

What I noticed with mine.... a little easer start in cold weather, and a little better running when cold, thats about it... I do rev 6.5-7K RPM.. but that is far and few in between...

BUT, I replaced 3 or 4 of them to date, they have left me high and dry in the middle of no where.... the last unit was a model change and I have had no problems with it to date... about 1 year now, so... knock on wood....

Would I recommend it to someone that never sees 6-7K and has a chock on there carb? No...

we just built my sons 360 amc jeep, nice rv cam... he ask the same thing... no, no msd for the jeep

why do i keep mine? 1. no choke... 2. hi rpm's at times 3. I purchased it, and damn it to heck!! I'm stubborn. yea... I just like it there..and I do not believe it gives me any more hp.. at least below 6K.... 4. for me.. Rev limiter

jmho.... and my 2c

p

 

You know something Lars doesn't?

 

The 6A is a piece of junk. digital multi sparks with the sequential rev limiter is what you want

Good wires Platinum plugs good coil

 

That was a VERY good read..... Thx!

 

For my money I'd go with an HEI. I ran them for years and they were bulletproof. I never out rev'd them and never had to put a penny into them.

I now have an MSD with a 6AL box and I don't like it at all. I never know if the box is malfunctioning because there is no good way to test it so I've had to send it to MSD twice. Every time I have a problem with anything I have to go through and eliminate everything but the box and then finally remove it and ship it to them for testing. This takes a minimum of two weeks round trip, more like 3. You have to pay shipping and then pay for them to test and then pay for repairs and for them to ship it back to you. Two out of two times I've had bad capacitors and resistors in the box. All I do is drive on the street and it is hooked up exactly to specs. I would never do this again.

Now, if they had a box that you could plug into and it would throw codes telling what was good or bad that would be different. I still wouldn't need it vs the HEI, but I might buy one of those for piece of mind since the system is already in there.

 

Gas and air need spark to burn and generate power, if the MSD will help with a more complete burning of the mixture, then they will generate more heat (and power).

 

This is the root of the misconception- the temperature the gas/air burns at has nothing to do with how 'strong' the spark is. Does your BBQ grill run hotter because you lit it with an MSD spark rather than a match?

The spark 'ignites' a handful of vaporized gas droplets that happen to be close enough to the arc. Those in turn light the ones next to them and so on until the flame front has spread to the entire combustion chamber. 'How hot' the original spark was becomes irrelevant.

As to the question 'do I know some thing that Lars doesn't'- of course I do- he doesn't know what I had for breakfast and I'm not sure he cares.

He partially explains his findings is this post, I'll defer to his experience

http://forums.corvetteforum.com/1563138679-post17.html

 

I have had my 6A in my BB since the 80's (made in the USA then) running flawlessly to present day - It starts my highly modified 11:1cr beast immediately when cold or hot and the performance is spectacular - Running with MSD Dizzy.

Since it was so "Old" I figured I'd change it out for a "new" 6A - The "new" one failed in 3 weeks! (Don't think they are made in USA anymore)

Put the "OLD" 6A back in and all is well!

Got to the MSD website support forum and read about all of the problems on the "NEW" units. (Analog and Digital)

IMO the quality of the electronic components are not as good as the "OLDER" units that were made decades ago. (like the one I have)

If you have a good running MSD Ignition - there is nothing as good! For the past 44 years I have had many ignitions in my 67 (due to multiple GM TI amplifier failures when the vette was new) and the MSD by far has been the best! No comparison to an HEI.

 

I wouldn't tell you to go out and buy one but since you have it I would install it. It has been many year but I noticed an improvement over the HEI stock distributor, easy starts, smoother idle and you can rev the crap out of it.

At 7000RPM I would rather have the 6AL in my car than the stock ignition

 

Im having what i believe to be an issue w the box as well. My 71 came with an msd distribuitor, msd blaster 3 and a 6AL box... im almost possitive i am getting no spark because of the box. Ran a few test (white wire to ground w/ screw driver in cable to coil 1/4 inch from ground) and i got nothing. Any eay i can just run the dist and coil by themselves and eliminate the box? Sounds to me thats keeping it might be more trouble than what its worth...

 

And sorry in advance for bringing up an old thread. I just bought the car and am desperate since its been dead for 2 weeks now.. Thanks for understanding and i look forward to your responses.

Dave