I have a 68 327 vette and looking to upgrade my HEI distributor that will work with my factory tach or one that has the electronic tach conversion? Can anyone send over some links on what is my best options

 

They’re not cheap, but DUI makes a top quality, high performance HEI with a tach drive for our C3s

 

Check this one out. Haven’t tried it myself...YET!

 

I also have the 68 327. I would love to know the difference in performance adding the HEI, or electronic ignition compared to stock points.

 

Absolutely none. The only thing you get out of an HEI is the zero maintenance. It will not make ANY more power.
The only things I see that are a benefit are slightly quicker firing time (first start) and the ability to leave the key in the on position.
NOW....if you go with the Davis DUI that was suggested above....you will see huge benefits due to the timing curve that they will put in it for you.
I dislike HEI's because they are huge and ugly......on a Vette they look like they do not belong there.

Jebby

 

That's what the shielding is for!!!

 

This is an interesting thread, but what I'm going to say has no bearing on these early year corvettes since they are not ECM controlled like the 81/82, more specifically the 82, but the info could be of some use to someone else reading this. SO, using a DUI HEI is a good move. However, there is something called SA Latency (spark advance latency) and has to do specifically with the HEI Module inside the distributor. With that being said, Davis will NOT give out the information about the latency they use in there modules specifically because they say it's propitiatory information, but they say it is similar to GM latency. Well, that tells me absolutely NOTHING! Why would you not supply the latency table information to a person that is tuning a motor so that they could update their SA Latency table tune to have the correct latency values to match their module (time between in ms that each cylinder is getting voltage) and cap size (small cap or large cap HEI) to run the motor efficiently and at optimum performance? I have contact DUI several times about this and they refuse to give out that information and the last time I contacted Mr. Davis directly.

Fortunately there is a way around all this, but it does get a little dicey. You must first zero out the latency table in the tune and run the motor manually in rpm at each of the rpm settings to see where you are at and manually set set each rpm range. The dicey part is when you get to the 4.5k range and up. BTW...My latency table was off on my tune after switching to a DUI dizzy. I had another noise issue I was seeing in the datalog with my original GM dizzy and why I switched to the DUI dizzy. Now that it has been corrected, it runs like the wind with no issues. I hope I didn't bore anyone with this info, but it may be useful to someone.

 

Interesting point, will shielding fit over an HEI? I have a ‘69 coupe if it matters. It also has a DUI HEI.

 

Guys,
Those of you more in the know than myself, can you please give this video a look and tell me your thoughts. Would an average guy have the capacity to plug in the optimum timing numbers/rpm assuming he would have access to the smartest among us on this forum to advise? I did not even know this existed and was about to pull the trigger on DUI performance distributor. Your thoughts?
Thanks!

 

I saw the video, and it looks like just what one would want as far as convenience, tunability, and performance. I have a DUI and like it, but I wish it had that tunability. I called Progressive Ignitions for some wanted info. You can change the cap, coil, or rotor if needed. Regular HEI stuff fits. But, the ignition module is proprietary........if It goes bad, you can't replace it from an auto parts store or Summit; that is a no-no for me.

 

These are all great responses, and I have an HEI right now that did help provide less maintenance and is very reliable. But didn’t work with my tach now I just want to get my tach to work with it. Here are the two types I was looking at

https://www.mamotorworks.com/corvett...h-drive-618578

https://www.mamotorworks.com/corvett...version-642254

 

I don't see why not. My '76 has the large factory hei cap and and factory shielding.

 

Longer usable plug life. The higher energy output from a genuine HEI ignition can better supply the additional energy needs of worn/fouled plugs.

 

Just watched Uncle Tony's Garage (youTube) and he showed a comparison between HEI and points. There was NO difference at all, and in some cases points won hands down. He only runs points. Has me thinking of staying with original distributor and points on my car

 

I have the PerTronix ignition. The main reason I like it, I don't have to worry about the points going bad or setting them. It takes one thing out of wondering what needs to be checked.

 

I have bought three off ebay one is in my 455 in a jet boat. The one for my 64 is billet has a tach drive and cost 59 bucks. Had the one in the 64 on a dyno works just like a 350 dollar one dose. But if your one of those people that thinks you get want you pay for then go ahead and spend your hard eared money on a name

 

So it sounds like a good move to take a distributor and install PerTronix for easy maintenance. Wouldn't that allow the shielding to fit over and the tach drive to work as well? I'm contemplating doing this for my '69 since I like the look of the shielding but didn't want
to haul out the dwell meter on each tune up.

 

I had a 69’ 427/400 a few years back and it had the stock distributor that I curved and had the Mallory trigger kit in it....sneaky and everything is as it was in 69’....including the original braided copper core wires.....started instantly and ran awesome....also could leave the key on with no fear....

Jebby

 

Thanks C3. Didn't even think of that. Deal killer for me too I'm afraid