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  #1  
Old Jul 25th, 19, 07:46 PM
Ironhead70 Ironhead70 is offline
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Default MSD or HEI

Trying to decide whether to junk my HEI dist. and go MSD dist and ign box or upgrade the HEI. Any comments are appreciated. SBC 355 alum heads 850 DP Holley.
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  #2  
Old Jul 25th, 19, 08:18 PM
Big Dave Big Dave is online now
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Default Re: MSD or HEI

Only thing wrong with an HEI box is it isn't a performance ignition. It hasa weaker spark and misfires as RPM increases. It is designed to go 100,000 trouble free miles in a production car not win on Sunday.

MSD and other brands of CD ignition boxes build an ignition system that delivers multiple sparks down lower in the RPM for better emissions and mileage, but still have plenty of power in reserve for high RPM use. A capacitive discharge box uses a different means of amplifying the spark to the coil than an HEI.

Big Dave
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  #3  
Old Jul 25th, 19, 09:03 PM
62 NovaWagon 62 NovaWagon is online now
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Default Re: MSD or HEI

From the factory the HEI is not a performance piece, but with a performance module and coil they are just as good as any other performance distributor, hard to beat a good HEI..
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  #4  
Old Jul 26th, 19, 03:00 PM
brian oneil brian oneil is offline
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Default Re: MSD or HEI

Hook MSD box to HEI, It removes the module. Easy to follow instructions and is a no brainer.
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  #5  
Old Aug 2nd, 19, 01:56 PM
Dave Ray Dave Ray is offline
 
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Default Re: MSD or HEI

There is no way to "fix" the in cap coils on large HEI's, but to use an MSD coil adapter kit, and GET THAT NIGHTMARE OF AN EPOXY FILLED DISASTER OUT OF THE CAP.

Ever hear some say "that HEi module isn't worth a darned, it falied FOR NO APPARENT REASON, 3 TIMES". then, after hearing that the module failures "can't possibly be from the coil failure's Dave Ray espouses to", a fully frustrated owner finally changes the coil, and the module failures miraculously STOP.

NOTHING ever fails for "no apparent reason". There is always a cause.

So, fix that large HEI, thy way we weren't allowed to do when the team at GM I was on developing the large HEI worked on them, get the coil out of the cap, use a round OIL FILLED coil standing straight up, and never look back, except to fix the emissions advance curves in them (which nobody seems to do correctly).

The RPM limiter in the large HEI is NOT the magnetic pickup, NOT the module, it is the C O I L in the cap. This is why both Mallory, and MSD offered the coil adapter kits for the coil in cap HEI's. There is only one kit left, MSD (Mallory is now owned by MSD, whom is now owned by Holley). Do not use any MSD Blaster coil, they are extremely problem prone.

These proven facts are why I NEVER use any in cap coil in a large cap HEI, ever.

Info to consider, both HEI and MSD box spark plug gap is limited to .045, any larger, and you invite coil, HEI module, MSD box failures.
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Old Aug 2nd, 19, 10:56 PM
62 NovaWagon 62 NovaWagon is online now
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Default Re: MSD or HEI

Quote:
Originally Posted by Dave Ray View Post
T

Info to consider, both HEI and MSD box spark plug gap is limited to .045, any larger, and you invite coil, HEI module, MSD box failures.
That is an absolute fact..
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  #7  
Old Aug 2nd, 19, 11:12 PM
62 NovaWagon 62 NovaWagon is online now
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Default Re: MSD or HEI

Quote:
Originally Posted by Dave Ray View Post
use a round OIL FILLED coil

Do not use any MSD Blaster coil, they are extremely problem prone.
What brand coil do you recommend?..
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  #8  
Old Aug 3rd, 19, 12:12 AM
Aukai Aukai is offline
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Default Re: MSD or HEI

Have Mr Ray make, or refurbish your HEI. Done deal....
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  #9  
Old Aug 3rd, 19, 04:43 PM
Dave Ray Dave Ray is offline
 
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Default Re: MSD or HEI

This IS NOT an ad, only info.

I do a different HEI design, one I designed, and developed.

The only services I offer for the large coil in ap HEI is to redo the curving for the ZZ series crate engine HEI's, and, I offer those changes and fix for absolutely free, no strings, no ads, so you can do them yourself, at home. . From that, I developed the vacuum advance stop plate info from doing a lot of ZZ distributors for a place in Whittier, Ca., Limeworks Speed Shop, as they used those ZZ4 engines in completely hand built cars they did from scratch.

I had noticed a lot of people not knowing much about vacuum advance, and how it really works, and about the advances themselves. I worked out that all aftermarket vacuum advances did not come with the as stock GM rubber bumper on the pull pin, so, when activated, the degrees the advances gave, were totally out of the park, giving 20, 30 plus degrees when the advance was plugged into the correct full manifold vacuum sourcing.

From there, I developed the correct way to mount the only sensible alternative, adding the Crane 99619-1 scroll degree stop to a GM vacuum advance. and before that, a set home made distance stop.

This info and procedures stopped a lot of top tuners and dyno hero's from making the giant mistake of ripping the vacuum advance off a distributor, or, leaving it disconnected, when it clearly would have made a significant improvement when set up correctly.

And, the use of a steel plate in plae of the rubber stop bushing is good, doesn't allow for time and conditions to have the rubber stop fall off the pull pin, and over time the engine.

Show of hands, how many have used my info to get their vacuum advances working correctly, and on the right vacuum sourcing, full manifold?

BTW, this isn't only for the large HEI, but all GM and other points distributors.

The HEI and vacuum advance stop info are still totally FREE, NO ads, NO strings, just ask for them.
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  #10  
Old Aug 3rd, 19, 09:17 PM
62 NovaWagon 62 NovaWagon is online now
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Default Re: MSD or HEI

I used your info and stop plate method, easy deal and works great and ALWAYS use full manifold vacuum....

You probably missed it, what oil filled coil do you recommend?, there's a lot of crap out there..
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  #11  
Old Aug 4th, 19, 06:54 PM
Dave Ray Dave Ray is offline
 
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Default Re: MSD or HEI

Didn't miss anything, just no recommendation, always starts a fight, and I am fed up with fights, being called liar, and other adverse things because someone else likes this or that other than what I do.

Here is a clue, stock GM points coils are great stuff, the basis for EVERY good performance coil, can be run with a resistor for drop in electronic points, points, and without a resistor for systems like HEI and MSD, that do not use a resistor.
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  #12  
Old Aug 4th, 19, 08:48 PM
62 NovaWagon 62 NovaWagon is online now
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Default Re: MSD or HEI

Hear ya loud and clear, don't blame ya.. And gotcha... Thanks Dave..
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