Full Size Jeep Network

After receiving a few suggestions to upgrade to an HEI setup, but knowing nothing about them, what all is involved in the swap? When there is how-to worthy info, it should be added to the tech library on here too.

When installing any distributor, you need to remove the old gear from the old distributor and install that old gear onto your new distributor. This way you have 'matched' gears and lessen the chance of a cam gear/dizzy gear failure.

HEI typically has the ignition module installed into the cap, which means it only needs 1 wire to make it run. That one wire needs to receive voltage whenever the key is 'on' and 'starting'. You can completely remove the old ignition box from the driver side fender and use the 'hot' wire from that to power the HEI.

Now there is some debate (in my mind) as to what is better HEI or TFI and personally think TFI edges out HEI IMHO.

I too am very intersted in this.
An I also am a blank slate in regards to knowledge on the subject.
If someone dosn't mind, could you please tell us what the different setups are, what the differences are, what the Benifits of each system is and if your feeling extra helpfull post a picture or two of each setup.

Thanks

Installed a Mallory HEI from Z&M Jeeps in Phoebe back in 2009. Used original Prestolite dizzy gear on the Mallory and in a couple months it chewed up both gears. No idea why at this point. I put new MSD gear on when we went put the VooDoo cam and double roller TC set in the next year. We power the HEI from the Prestolite power lead. Works great. Simple solution to stock ignition with fewer parts. We have done 3 Jacobs systems and HEI is hands down a simpler solution.

TFI and HEI are about the same in performance, the TFI is a little easier to maintain in my opinion.

Jacobs works great, for about 3 years (my experience). Unilite is a good alternative to stock, easy to install, decent performance and easy to tune.

No experience with MSD, no experience with Mallory HEI.

I love the HEI system I have in my 77 Cherokee from MSD, simple to install, easy to maintain, and much cleaner as well as better spark and better spark distribution. The only issue is making sure your gears are matched, either new or matched old ones. Plug in your firing order and your Jeep will fire the first time every time.

Just to muddy the waters a bit here I installed a new DUI HEI distributor with its new gear in my 1973 wagoneer with 135k miles in Feb. ,2003 and so far haven't had to do a thing to it yet. No problems with the new gear chewing up the old cam gear or vice versa and it always starts hot or cold. Part of that always starting is probably due to the Howell tbi as well . Don Sterling

nod58 wrote:Just to muddy the waters a bit here I installed a new DUI HEI distributor with its new gear in my 1973 wagoneer with 135k miles in Feb. ,2003 and so far haven't had to do a thing to it yet. No problems with the new gear chewing up the old cam gear or vice versa and it always starts hot or cold. Part of that always starting is probably due to the Howell tbi as well . Don Sterling

I think DUI has their stuff together on the HEI dizzys, I would still strongly recommend changing out the gear on the dizzy for the old gear, and this is especially for any of the aftermarket HEI dizzys that you can find for cheap on ebay... I bought one of the cheap ones off ebay, and they said their gear wouldn't eat my cam, well it did, and I am currently changing out the motor now because of it.. Don't get me wrong, I knew the risk and went with their word, and I am still going to use this dizzy on my new motor, but I am matching the gear sets this time...

I picked up a HEI from Summitracing, have yet to install it.

I did a "partial-TFI" upgrade (larger cap/rotor, MSD Blaster Coil) and noticed an immediate improvement in idle quality and quick starts. Then my distributor and ignition module started giving me problems so I decided to switch to an HEI. It could have been that the module/distributor was going out but I have to say that the HEI made a huge difference all around. Faster starts (basically immediate), smoother idle, and it even seemed to accelerate much stronger/smoother. And honestly my favorite things about the HEI is the simplicity of one wire hookup and the ignition module and all of the wires not being on the fender anymore. Just my .02

My opinion is that the TFI and HEI are so damn close that you couldn't tell any difference if both are working correctly. I go for simple and you can't beat one wire to the HEI and throwing all that stock wiring mess as far as you can.

Be sure to properly open up the gap in your new plugs to take advantage of the hotter spark in either case. You don't want to use the stock gap size or you negate a lot of the benefit.

Sent from my iPad using Tapatalk HD