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Discussion Starter · #1 ·
I have been watching the posts now for the past couple of months regarding the mods to the Duraspark and how it is supposed to be better than the HEI dist. For what its worth, I made the Duraspark mods (but not the Nutter bypass) to my 84 CJ about 3 years ago and I got good results. I gained about 2 MPG and better all around performance. However, I still had problems on the upper end. When I installed the HEI, it 'woke up' my 258. It has never ran better.

Has anyone else tried both mods? If so, what were your results? I'm open minded and believe that there is a chance that maybe I have something else wrong. I am even considering putting my Duraspark back in to see if I can find anything wrong. If there is someone who has tried both and gets better performance with the Duraspark..then I will go back to it. Otherwise, I'm staying with the HEI.


John......southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak
 
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Discussion Starter · #2 ·
I'll be trying out the Duraspark upgrade with the TFI coil in then next few weeks (limited budget in skool ya know?) I have the HEI now and I've been very pleased with the performance - but I really want the advance curve set exactly as stock. I'm pretty maticulous when it comes to timing (because I've seen what a little too much advance or retarding can do!) and the HEI just doesn't seem to want to match up with my low and high end RPM ranges and 89 octane gas (It loves 93... but I can't afford it!) -No matter what springs, or weights I try, or the adjustable vacuum diaphram. So I'm hoping that the old distributor with the new coil will resolve some issues - if not the HEI will still be ready to go. I'll keep you posted DDawg.
Later.
Sully

 

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I just took off the HEI and did the duraspark thing.(because I could do it for free) No real change in performance.(thats good) And the duraspark is super easy. My guess is you never changed the advance springs in the dist.(did you use a cannister coil or a TFI?) Thats what "wakes" up the ford unit like the HEI. The parts are WAY cheaper for the ford and easy to get anywhere in case I'd need them. I sold my HEI./wwwthreads_images/icons/wink.gif

I knew everything when I was 16......How come I'm so stupid now?
 

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Dirt Dog is probably correct.
If you didn't get the fast springs, that is the difference.
An AMC engine is more like a GM than a Ford in the advance department. They like a lot of it quick!
Fords are a little more reserved, and do the centrifugal thing a little slower.
Just by changing springs, you can wake the engine up quite a bit.

On the dyno, a spring change wasn't worth any extra total horsepower, but it did bring the horse power and torque in much faster. That's the extra 'Zip' some people get with the GM HEI.

I don't recommend changing springs unless you intend to upgrade the entire ignition.
It's just the next step in performance upgrades...

Under NO circumstances should you let an engine DETONATE! If you do the spring upgrade, make sure you adjust the initial to where the engine doesn't 'spark knock'! That is detonation, and it will kill the engine.
If your engine spark knocks, back the initial timing off two degrees at a time until it doesn't do it any more.
If you get below 6 degrees before TDC, and it's still spark knocking, you may have to go to stiffer springs or look for another problem.

If Chris Columbus "Discovered" America (with 25 million already here), Can I Go "Discover" Florida?
 
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