distributor upgrade need insight

I have a cj5 and im looking to get rid of some extra wires and upgrade abit. 304 stock I have in it, wanting to do a distributor up grade. Heard some neg discussion of HEI, DUI about the gears breaking off them or grinding up. Figure if I put a DUI in her i can get rid of the ignition module and the coil correct? as the distributor has these included in them. Anyone done this? pro's con's.
It's been sitting for 8 yrs and it's time to get it back on the road. So i figure if im replacing the modules, solinoids, etc may as well upgrade them for the extra money, good as time as any.
Insight would be appreciated. Im fairly mechanically capable but the jeep is a new toy so looking for some insight b4 jumping in. Thanks in advance.

 

This should be in the intermediate tech forum. Perfectly reasonable question for there.

What year is your Jeep? Which distributor do you have now?

I would recommend the 78-79 Jeep V8 distributor with the TFI upgrade. How deep are your pockets? The MSD module is said to work well, and that's what I will be using on my CJ. Otherwise, I'd use the stock Motorcraft module with that distributor.

 

x2 what Tim said. You can upgrade any AMC v8 to a motorcraft dizzy and do the TFI upgrade. That is what I'm going to do when the time comes.............

 

my jeep is a 75 thanks take it the thread is moved. !st time adding didnt really know where to put thanks again

 

If you have the money, go with the DUI unit. Just make sure to use the original distributor gear with whatever dizzy you decide to use.

 

Have u used a DUI or known anyone who has? Heard good things as long as of course the gear doesn't grind offf or blkow apart lol. Think it may b a good upgrade for 400

 

http://http://www.earlycj5.com/forums/showthread.php?t=64494

This is what I did. Should be the same as your 304.

 

Holy cripes - $400? Seems like a lot of money for putting all the components under the distributor cap.

In a '75, you have the Prestolite ignition system, which is not great - I'd advise replacing it.

You can buy a reman '78-79 Motorcraft AMC V8 distributor (Duraspark) for about $50. The DUI is a glorified GM HEI, and uses the same physical principles (variable reluctance) as the Motorcraft distributor. Do your homework about which parts to buy ... there's tons of info on the net about using Ford TFI parts with the Duraspark distributor.

There's lots you can do with stuff from the parts store and junkyard re ignition upgrades.

 

The TFI works, and is a cheap upgrade. It doesn't get rid of any wires though. The DUI is a spendy unit, but is built better than the other HEIs and will be taylored to your specs. Customer service is great too. I myself run a Motorcraft dizzy with a MSD 6T box. Works very well, but close to the price of the DUI, and has more wires.

 

IMO properly routed wires are just as tidy, and putting the coil in the distributor has some serious technical drawbacks. Not convinced that any variant of the HEI is such a great idea, when you can get a distributor that was meant for the 304 from an OEM source, complete with an OEM gear that should work fine with your cam gear.

 

I got both and i can't them apart. got a 74 with hei and a 79 with TFI..both run great.

 

I have this one from Mallory... Works great!

http://www.malloryperformance.com/P...onName=Select+Aspiration&brandName=All+Brands

 

i ran the malory dist in my 70 chevelle with a 400hp 350. They are a nice dist in tight spots and work great.

 

Thanks to all who replied. much appreciated. Will give it some thought

 

I made a spread sheet that shows a few options possible with the Duraspark distributor:



Lots of options. Hope you find this helpful.

 

What ever you choose, make sure to use your original gear. It doesn't matter if you buy a factory dist. with an OEM gear, the new gear will eventually eat your cam gear because it is not wear matched. This is not a myth, do the research.

 

If you look you can find a new complete hei for about $150 and put your gear on it. DONE No more wires, the most common cap in the world, easy to carry a spare module. Plug one wire into it and never have to mess with it again.

 

I'm a little puzzled by all this "keep your old gear" stuff... We are talking about distributors from 3 different manufacturers here (4 if you include the Delco points distributor, used before 1975) - [1] the aftermarket GM HEI (and the DUI), [2] the Prestolite used by Jeep '75 through 77, and [3] the Ford/Motorcraft Duraspark, used by Jeep from '78 on.

The OP has a Prestolite, and I doubt very much that the Prestolite gear will fit on either the HEI or the Duraspark distributors without some modification, and maybe not at all. I also doubt you can swap gears around between the other types of distributors - maybe the Delco gear will fit on the HEI distributors, maybe not.

My understanding is that there were a batch of inexpensive HEI distributors that were shipped with hardened steel gears. These aftermarket gears will tear up your original cam gear. However, to the best of my knowledge there is nothing in the FSM that says you must match the cam gear to the distributor gear - the parts catalog lists these separately, so you should be fine with any OEM Jeep cam gear meshing with an OEM Jeep distributor gear, ie with a Duraspark swap.

If you want the HEI, the most cautious approach would be to buy a matched set HEI gear and cam gear from Bulltear and replace the cam gear when you replace the distributor. If you think you are going to try and keep your original distributor gear, you better do some additional research and make sure you can swap the gears. Or else trust the seller to give you a distributor that won't eat up your cam gear.

<edit> Looking at the parts book, the Delco gear 3198787 is different from the Prestolite and Duraspark gears (3208615). I'd guess that the gear from the Delco points distributor might fit on the HEI distributors, since the two parts are both sourced from GM. The OP can put his original gear on a Duraspark distributor, but I expect it won't work on a HEI.

 

I did an HEI swap a few weekends ago and when I pulled the stock dizzy and peered down the hole with a flashlight... the cam gear was already looking to me like it was a little 'chewed'. The edges of the gear were not the usual uniform machined look and they looked a little thin. A little rough feeling along the edge with your finger. I was able to swap gears from the old to the new. I know I'm sitting on a time bomb but I figured using the old gear would give me more 'time' than dropping a brand new 'sharp' gear in there.

The other thing that I noticed that wasn't mentioned yet was that upon dropping in the new dizzy it's flange wouldn't seat completely flat on the block face. I had to shave a few millimeters off the bottom of the dizzy shaft where it fits into the oil pump drive. It was bottoming out on the oil pump.