I run a 70 318.I have never removed the gasket from any spark plug except the slant six drool tube engines. I have the ZFR5N plugs in my stock slant six but I have modified my 318 quite a bit so I would be hesitant to try them in it.That being said,in your stock 318 I would imagine there should be plenty of clearance for the ZFR5N plugs. To give you an idea of how far down the hole those pistons are at TDC I fitted a 360 stroker crank ,same length rods and used a low comp 318 truck piston and it came out at zero deck and 10/1 comp. You don't need a micrometer to measure how far the piston is down the hole on these old Mopar engines,you need a telescope!

Thanks. I ordered some ZFR5N spark plugs today. I'll just install them as-is, including leaving the .035" gap as is, and see how it goes.

I think that's a good starting point,I ended up at .040" on the slant,but like Duster Idiot said its all of combo of tuning,mixtures,timing etc.One thing for sure is that the HEI give s you the opportunity to unlock a little more efficiency out of these engines.

I just found this in the latest car craft magazine on this subject, thought I'd share.





Flipped for easier reading here.
Aspen76

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76 Dodge Aspen
225 Super Six w/ Dutra True Dual Exhaust

http://i1245.photobucket.com/albums/gg5 ... AG0095.jpg
http://www.youtube.com/user/BZuko1?feature=guide

Jeeze, I remember working on this over a decade ago with goldduster318. Looks like the mainstream FINALLY picked up on it!

http://duster318.freeservers.com/tech/hei.html

I know its all been covered already, but IM bored and wanted somewhere to post... Been on the car for almost 2 years now. Had one module fail, but it was used and an unknown brand I used for mock-up/testing.

Here is where it is at now, and has been for a while... MSD module, 5-pin relay, standard fd478 coil, and a home made bracket assembly... There was no drilling or cutting into the car, and only spliced into the factory "start" wire... NGK UR4 plugs @ .045", accel super stock 8mm wires... Module mounts on a bracket just below the coil bracket, and the relay mounts just above. The extra connector attached to the green wire of the coil is just a quick spot to connect a tach for testing... Power is pulled from an extra accessory fuse panel I installed previously.


However, I do have this mocked-up and a friend going to be fabbing up a metal box like this that will bolt down onto the fender where the old mopar ICM was mounted. As you see it will house the module, relay and noise suppressor as well as the majority of wiring.

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"if it aint broke, fix it till it is"
78 Plymouth Volare Super Six wagon
89 Volkswagen Golf GTI 16v
92 Chevrolet K1500 5.7
98 Ford Escort ZX2 zetech

Here is the post with MaximRecoil's HEI circuit drawing
Here is the drawing:


Charrlie_S's words make all my 3 braincells tingle every time I see that drawing, as there are not many wires to misplace.

But, MaximRecoil's otherwise excellent drawing is incorrect, in that the ignition lock should have a positive current input, and it's output should provide the relay wih positive current to activate it. No need for ground on a switch that only turn the current ON/OFF.
I hope it will be redrawn correctly.

Olaf

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Aspenized

85 and 86 are switching, polarity is unimportant. 30 is power in, 87 (and 87a if present) is/are power out on relay.

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Dave

1977 d-200 crew cab ex-army pickup wants it's /6 back
1962 Valiant 2 door, 170, three on the tree
1972 d-100 parts truck
80 volare wagon now a parts car

Most of the time 85 & 86 are unimportant.......

Sometimes the relay has a flyback diode between 85 & 86.

So use the 85 on the grounding side just incase.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Something learned!

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Dave

1977 d-200 crew cab ex-army pickup wants it's /6 back
1962 Valiant 2 door, 170, three on the tree
1972 d-100 parts truck
80 volare wagon now a parts car

Not slant related, but HEI related and just thought Id share my experience.... I work at an auto part store, so I see all kinds of things and have looked up about every part under the sun for thousands of vehicles.... This one particular is an 86 Jag XJ-S, no start issue and the customer got prices on the ignition module... Cost from us was $496+tax!!! So he decided to open this module box, and what we found was shocking... A simple little $20 4-pin GM HEI module and capacitor inside. Even stamped GM with a GM part number....

That has got to be one of the biggest automotive rip-offs I have come by yet! Also makes me wonder how many others out there do the same stuff.

On another note though, it was a clean looking little box and would look great for conversions if the price wasnt so incredibly high!

_________________
"if it aint broke, fix it till it is"
78 Plymouth Volare Super Six wagon
89 Volkswagen Golf GTI 16v
92 Chevrolet K1500 5.7
98 Ford Escort ZX2 zetech

This is how it should have been drawn. https://onedrive.live.com/redir?resid=D ... hoto%2cJPG
As drawn the original circuit will not work.

Dave

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86 Miser 170,000+
2 1/4" exhaust
Holley 1920 #55
HEI MSD BLaster 2
17.8 mpg

Just wondering how hot the module normally runs. Is it something that you can put your hand on and it feels warm, or too hot to leave your hand on, or burning hot to touch quickly.

Also what are the symptoms of a module failing with heat. Do they work fine up until they stop, or do they start giving poor running prior.

I currently am having an issue with poor idle when engine is hot. It almost sounds like it has a burnt valve / sticking valve, but compressions check out perfect, vacuum is stable. (hydraulic lifter motor too)
I’ve tried two carbies and it does the same.
Everything is new on the ignition side.

Starting to run out of ideas to check. It runs fine on the cruise / power but comes back to a lumpy poor idle.

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1967 VC Valiant

The modules were often mounted inside the distributor in the original GM design...so they can be pretty hot and still survive ,but after saying that, they must have a good heat-sink. The heat of the module will vary on how much current it's handling,a lower resistance coil will make them get hotter. I've seen a lot of pretty big heat sinks that guys have used in conversions....won't hurt,the cooler the better I guess,but considering where they were originally designed to be mounted I'd say they are a pretty tough unit. I know I have mine mounted on an alloy heat sink,which is bolted to the inner guard which gives even more heat transfer,I run a .3 ohm coil from memory. Just idling it's barely warm,after a run at a decent rpm it's certainly a little hotter,but I can still touch it. Hope that helps!

Mines bolted to a steel bracket bent to a 90* and mounted to the passenger inner fender. I have yet to feel it barely get warm (MSD module), even after a long haul out to Sacramento (2hr drive @ about 60-70mph)... Running a .5ohm Ford TFI coil.... Also completely isolated from the factory wiring, relay powered from extra fuse panels I installed under the dash, and an extra ground wire from the batt (-) to the coil/module bracket.

From experience, misfires or sputters are caused from poor power/ground sources, or getting interferance between the dizzy and module. So Id start there. Usually the just quit completely when hot, then SOMETIMES work pretty good for a little while after they cool off. However nothing is impossible, and the quality of most over-the-counter modules are questionable at best...

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"if it aint broke, fix it till it is"
78 Plymouth Volare Super Six wagon
89 Volkswagen Golf GTI 16v
92 Chevrolet K1500 5.7
98 Ford Escort ZX2 zetech