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Unread 12-31-2013, 11:49 AM   #1
tomcat77
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prestolite to motorcraft ignition swap question

Can the prestolite ignition coil be used when swapping to the motorcraft ignition?

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Unread 12-31-2013, 12:51 PM   #2
CSP
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Any 12v negative ground coil will work. There's nothing special about coil wiring that differentiates them from one system to another.
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Unread 12-31-2013, 01:10 PM   #3
tomcat77
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Ok thanks. Thats what I thought but wasn't sure because the coils have different part numbers for a 77 304 and the 78 when they changed to the motorcraft ignition system. Looks like the only difference is the wire attatchment. The prestolite has threaded terminals and the motorcraft has the horseshoe clip terminals like Fords use.
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Unread 12-31-2013, 02:06 PM   #4
CSP
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Yep, that's the difference.
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Unread 12-31-2013, 02:17 PM   #5
JeepHammer
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Different electrical resistance in the coils between ignition models...

If I were doing a switch, I would switch the coil.
Not to another factory 'Socket' type coil, but to an E-core coil with better terminal and properties to produce ignition spark energy.
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Unread 12-31-2013, 02:44 PM   #6
tomcat77
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Ok thats what I didn't know if there was an electrical difference. I will go with an accel or msd. Don't need anything fancy. The 304 is all stock except for the edelbrock 500 carb and air gap intake.
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Unread 12-31-2013, 10:17 PM   #7
86cj74.2L
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Quote:
Originally Posted by JeepHammer
Different electrical resistance in the coils between ignition models... If I were doing a switch, I would switch the coil. Not to another factory 'Socket' type coil, but to an E-core coil with better terminal and properties to produce ignition spark energy.
The e-core coil with the stock duraspark module may be too much current. Their only rated at 2a. Plus the preset dwell in the ICM is set for a can type coil with lots more iron. The e-core only needs about half the dwell a can type needs.
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Unread 01-01-2014, 07:55 AM   #8
JeepHammer
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Quote:
Originally Posted by 86cj74.2L View Post
The e-core coil with the stock duraspark module may be too much current. Their only rated at 2a. Plus the preset dwell in the ICM is set for a can type coil with lots more iron. The e-core only needs about half the dwell a can type needs.
Depends on the module he uses.
If it were me, I'd use the Jeep/Motorcraft distributor,
Cap & Rotor Upgrade,
Really good plug wires, well worth the money spent,

And I'd use a GM HEI style module and E-core coil.
HEI style module give him full power capabilities to the coil for more output,
And it's E-core compatible (not to mention $30 or more cheaper than the weaker DuraSpark module clones at the discount stores).

With a modular system like this, you get to pick and choose the best components for the application,
And in this case, save the money on the distributor, use a factory Reman, around $50...

Use a BRASS TERMINAL cap, and brass terminal rotor nose, if you can find one,
Use the upgraded, larger cap, taller rotor, ignition upgrade parts on the factory distributor for better handling of the spark energy on the way to the plugs,

Use the best plug wires you can afford.
You will only do this once, maybe twice in the time you own the Vehicle if you use top quality wires,
And you are going to the trouble to MAKE this extra spark energy,
It doesn't make sense to choke on wires and NOT get that spark energy to the plugs...

The HEI style modules are cheap, they work, they are available everywhere off the shelf... And they work with E-core coils, which have the better coil wire terminals over the round 'Canister' coils...

And I'd use an E-core coil, preferably out of a Ford vehicle from a salvage yard.
You can pick up the coil NEW for around $50=$60, but it's about $5 at the salvage yard, and you can get the bracket/connector plug at the same times saving you even more money.

Coils don't (normally) go bad, and Ford use a top quality coil (Trying to fix an issue with the TFI ignition... That wasn't the coil! So we benefit from those great quality coils!)

Since the distributor, cap, rotor, coil and module are all off the shelf, this is stuff that can be replaced easily and cheaply in the future...
And it's all safe for the vehicle.

If you have a salvaged Jeep or Motorcraft ignition harness in good shape, I'd use the old ignition module case for a 'Heat Sink' for the GM HEI module,
And I'd do "John Strenk's" version of the 'Stealth HEI Conversion'.
This makes everything 'Plug & Play' and look factory (or better if you take a little time with the wiring)...

Nothing like the factory plug to make swaps/repairs a snap!
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